Geography Set 14
π
π Physical Geography β’ Himalayas
Q.1) According to the geological history of the subcontinent, the third major upheaval of the Himalayas took place about 1.4 million years ago. During which geological period did this occur?
Ans > (C) Post-Pliocene Period
- Explanation: The third upheaval took place during the Post-Pliocene period, about 1.4 million years ago, which resulted in the folding of Shiwaliks or the Outer Himalayas.
- Phases of Himalayan Orogeny: The Himalayas are young, fold mountains formed by the ongoing collision of the Indian Plate with the Eurasian Plate. This monumental upliftment did not happen all at once but occurred in three major, distinct geological phases spanning millions of years, which successfully closed the ancient Tethys Sea.
- The Post-Pliocene Tectonic Event: The third and final major upheaval occurred during the Pleistocene epoch (often referred to as Post-Pliocene in older geological texts), roughly 1.4 to 1.7 million years ago. This specific tectonic event folded the fluvial sediments brought down by older Himalayan rivers, giving birth to the Shiwalik Range.
- Composition of the Shiwaliks: Because the Shiwaliks (Outer Himalayas) were formed much later than the Great and Lesser Himalayas, they are predominantly composed of unconsolidated sediments like gravel, sand, mudstone, and conglomerate. This geological youth makes the entire region highly susceptible to landslides and rapid soil erosion.
- Ongoing Geological Activity: The intense tectonic forces that triggered this third upheaval have not ceased. The Indian tectonic plate continues its northward journey into the Eurasian plate at a rate of roughly 5 centimeters per year, meaning the Himalayas are still rising and the region remains a highly active seismic zone.
π Physical Geography β’ Quaternary Glaciation
Q.2) During the Quaternary Period, the Pleistocene epoch was marked by Ice Age conditions and large-scale glaciation in the Northern Hemisphere. To what altitude did the ice-sheets descend in India during this period?
Ans > (C) 1500 metres
- Explanation: During the Quaternary Period, the ice-sheets descended to as low as 1500 metres in altitude.
- The Pleistocene Ice Age: The Pleistocene Epoch, which began about 2.6 million years ago and ended roughly 11,700 years ago, is famous for its multiple glacial events. During this time, massive ice sheets advanced and retreated across the Northern Hemisphere, drastically altering global sea levels and climate.
- Glaciation in the Indian Subcontinent: While the Indian peninsula remained largely free of continental ice sheets, the Himalayan region experienced intense alpine glaciation. The global drop in temperatures caused the permanent snowline to lower significantly, allowing massive glaciers to descend into valleys as low as 1,500 meters above sea level.
- Geomorphological Footprints: The legacy of this massive glaciation is still clearly visible in the modern Himalayan topography. The descent of these heavy ice sheets carved deep U-shaped valleys, created hanging valleys, and left behind massive deposits of glacial till and moraines that now form the fertile, terraced slopes of the lower Himalayas.
- Impact on Flora and Fauna: The descent of the ice sheets forced high-altitude flora and fauna to migrate to lower elevations to survive. As the Pleistocene epoch ended and the Holocene (our current epoch) began, temperatures rose, causing glaciers to retreat and stranding many of these cold-adapted species in high-altitude “islands” within the mountain ranges.
π Indian Geography β’ Peninsular Plateau
Q.3) Forming an irregular triangle with its base lying between the Delhi Ridge and the Rajmahal Hills, what is the general elevation of the peninsular upland?
Ans > (B) 600β900 metres
- Explanation: With a general elevation between 600-900 metres, the region constitutes an irregular triangle with its base lying between the Delhi Ridge and the Rajmahal Hills.
- The Ancient Gondwana Landmass: The Peninsular Plateau is the oldest geological landmass in India, having once been a central part of the ancient supercontinent of Gondwana. Unlike the young, folded Himalayas, the peninsula is a highly stable, ancient shield region primarily composed of hard igneous and metamorphic rocks.
- Topographic Boundaries: The plateau forms a distinct irregular triangle. Its northern boundary is roughly defined by a line running from the Delhi Ridge, extending eastward along the Vindhya ranges, and terminating near the Rajmahal Hills in Jharkhand. The apex of this triangle points downward toward Kanyakumari.
- The Regional Elevation Gradient: The general elevation of this vast tableland ranges between 600 to 900 meters. However, it is not perfectly flat; the plateau has a distinct tilt. It is higher in the west and slopes gently towards the east, which dictates the flow direction of most major peninsular rivers like the Godavari and Krishna.
- Sub-divisions of the Upland: Due to millions of years of river erosion and tectonic faulting, this continuous landmass is broken into several distinct smaller plateaus. These include the Central Highlands (like the Malwa and Chotanagpur plateaus) in the north and the expansive Deccan Plateau situated south of the Narmada River.
π Indian Geography β’ Drainage Systems
Q.4) The Malwa Plateau features a dual drainage system. While rivers like the Chambal and Betwa flow towards the Bay of Bengal, which of the following rivers drains towards the Arabian Sea?
Ans > (D) Mahi
- Explanation: The Malwa Plateau has two drainage systems, one towards the Arabian Sea (Narmada, and Mahi), and another towards the Bay of Bengal (Chambal, Sind, Betwa and Ken) joining the Yamuna river.
- Geographic Positioning of Malwa: The Malwa Plateau occupies a central position in western India, situated squarely between the Aravalli Range to the northwest and the Vindhya Range to the south. It is characterized by its rolling plains and deep ravines, largely formed by ancient lava flows that weathered into fertile black soil.
- The Continental Divide: The plateau acts as a critical water divide in the Indian subcontinent. The slight variations in its topography cause rainfall to split into two entirely different oceanic destinations. This dual drainage system is a defining geographical feature of central India.
- The Arabian Sea Drainage: Rivers such as the Mahi and the mighty Narmada represent the western drainage system. The Mahi originates in Madhya Pradesh, flows through the Malwa region, enters Rajasthan, and eventually empties into the Arabian Sea via the Gulf of Khambhat in Gujarat.
- The Bay of Bengal Drainage: The northern and eastern slopes of the plateau drain into the Ganga-Yamuna river system. Rivers like the Chambal, Betwa, Sind, and Ken carve deep gullies (notably the Chambal Badlands) as they flow northeastward to join the Yamuna, eventually making their way to the Bay of Bengal.
π Indian Geography β’ Meghalaya Plateau
Q.5) The Shillong Peak (1823 m) is the highest elevation in the Meghalaya Plateau. Which of the following is the highest peak specifically of the Garo Hills?
Ans > (C) Nokrek
- Explanation: The Shillong Peak is the highest elevation (1823 m) in the Meghalaya Plateau, while Nokrek (1515 m) is the highest peak of the Garo Hills. (Note: Nokrek is the correct spelling).
- Geological Origins of Meghalaya: Although located in Northeast India, the Meghalaya Plateau is not geologically part of the Himalayan mountain chain. It is actually an eastward extension of the ancient Indian Peninsular Plateau, separated from the main block by the Malda Fault (or Garo-Rajmahal Gap) in West Bengal.
- Divisions of the Plateau: The plateau is traditionally divided into three distinct hilly regions based on the indigenous tribes that inhabit them: the Garo Hills in the west, the Khasi Hills in the center, and the Jaintia Hills in the east. Each region has distinct topography and microclimates.
- Nokrek Peak and Biosphere: Nokrek is the highest point of the Garo Hills, standing at an elevation of 1,515 meters. Surrounding this peak is the Nokrek Biosphere Reserve, renowned for its rich biodiversity, including the rare red panda and ancient species of wild citrus plants (Citrus indica).
- Climatic Significance: The funnel-like shape of these hills traps moisture-laden Southwest Monsoon winds sweeping in from the Bay of Bengal. This unique orographic configuration results in exceptional rainfall, making places within the plateau, such as Mawsynram and Cherrapunji, the wettest locations on Earth.
π Indian Geography β’ Dandakaranya
Q.6) The Dandakaranya is an undulating plateau sprawling over Orissa, Chhattisgarh, and Andhra Pradesh. It is primarily drained by the Sabari and Sileru rivers, which are tributaries of the:
Ans > (A) Godavari River
- Explanation: It is drained by the Tel and Udanti, tributaries of Mahanadi, and the Sabari and Sileru, tributaries of Godavari rivers.
- Historical and Cultural Significance: The term “Dandakaranya” translates to “The Jungle of Punishment” in Sanskrit. It holds immense mythological importance as it is prominently featured in the Hindu epic Ramayana as the dense, demon-inhabited forest where Lord Rama, Sita, and Lakshmana spent a significant portion of their exile.
- Geographic Coverage: Today, this rugged, undulating plateau region covers a vast area in central-eastern India. It predominantly spans the Bastar division of Chhattisgarh, the Koraput and Kalahandi districts of Odisha, and the border regions of northern Andhra Pradesh.
- River Systems and Drainage: The hydrology of Dandakaranya is defined by two major peninsular river basins. The northern and eastern sections are drained by rivers like the Tel and Udanti (tributaries of the Mahanadi). The southern and western sections are drained by the Sabari and Sileru rivers, which flow southward to feed the Godavari River.
- Resource Wealth and Ecology: The Dandakaranya region is one of the most resource-rich areas in India, possessing massive deposits of iron ore, bauxite, and limestone. It is also heavily forested, featuring dense tracts of Sal timber, and serves as a vital habitat for indigenous tribal populations and diverse wildlife.
π Indian Geography β’ Karnataka Plateau
Q.7) The Nandi valley is a well-known summer resort located in the southern part (Maidan) of which of the following plateau regions?
Ans > (D) Karnataka Plateau
- Explanation: The northern upland of the Karnataka plateau is known as Malnad, while the southern part is called a Maidan. It is drained by the Kaveri and the Tungabhadra rivers. The Nandi valley is a summer resort in this region.
- Topography of the Karnataka Plateau: The Karnataka Plateau (also known as the Mysore Plateau) is a prominent southern sub-division of the Deccan Plateau. Geographically, it is bordered by the Western Ghats to the west and the Eastern Ghats to the east, merging where the two mountain ranges meet at the Nilgiris.
- Malnad vs. Maidan Regions: The plateau is geographically classified into two distinct zones. The “Malnad” (meaning hill country) represents the deeply forested, rugged, and hilly terrain adjacent to the Western Ghats. The “Maidan” represents the lower, gently rolling, open plains that dominate the eastern and southern portions of the state.
- The Nandi Hills Attraction: Located in the Maidan region just north of Bengaluru, the Nandi Hills (and the surrounding valley) serve as a prominent hill station and summer resort. Historically, the area was used as a strategic summer retreat by Tipu Sultan, and it remains a vital geographic landmark.
- Hydrological Importance: The Maidan region, including the Nandi Hills, serves as a crucial watershed. The Nandi Hills are the origin point for several important rivers, including the Arkavathy, Penna, and Palar, while the broader plateau is heavily drained by major systems like the Kaveri and Tungabhadra.
π Indian Geography β’ Western Ghats
Q.8) The Palakkad Gap (Palghat) joins Tamil Nadu with the coast of Kerala and allows the Gayitri river to flow through from east to west. What is the approximate width of this broad gap?
Ans > (C) 24 km
- Explanation: Between Coimbatore and Anaimalais, there is a broad gap, known as Palakkad Gap (Palghat), about 24 km wide, through which flows the Gayitri river.
- A Major Geographic Breach: The Western Ghats run almost continuously for 1,600 kilometers along India’s western coast. The Palakkad Gap represents the single most significant break in this mountain chain. Measuring approximately 24 kilometers wide, it acts as a massive natural gateway through the otherwise impenetrable mountains.
- Tectonic Origins: Unlike most mountain passes which are carved purely by river erosion over millennia, geologists believe the Palakkad Gap has tectonic origins. It is considered a shear zoneβan ancient fault line that was weakened by tectonic activity and subsequently eroded down to its current low elevation.
- Climatic Influence: This wide gap profoundly affects the regional climate. During the Southwest Monsoon, it funnels moisture-laden winds straight into western Tamil Nadu, bringing rainfall to Coimbatore. Conversely, during the winter, it allows hot, dry winds from the eastern plains to blow into Kerala, raising local temperatures.
- Strategic and Commercial Trade: Historically and currently, the Palghat Gap is of immense economic importance. It seamlessly connects the fertile coastal plains of Kerala with the industrial and agricultural heartlands of Tamil Nadu, serving as the primary corridor for highways, railways, and major trade routes between the two states.
π Indian Geography β’ Eastern Ghats
Q.9) While the Western Ghats have a higher continuous elevation, what is the average height of the highly detached and heterogeneous Eastern Ghats?
Ans > (B) 600 m
- Explanation: The average height of the Eastern Ghats is about 600 m.
- Geological Antiquity: The Eastern Ghats are ancient, highly weathered relic mountains that are generally much older than the Western Ghats. They trace parallel to the eastern coastline of India, running from the Mahanadi valley in Odisha down to the Nilgiri hills in Tamil Nadu, where they merge with the Western Ghats.
- Average Elevation and Peaks: Compared to the towering Western Ghats (which average 900-1600m), the Eastern Ghats are significantly lower, with a general average elevation of just 600 meters. However, specific peaks can be much higher, such as Arma Konda (Jindhagada Peak) in Andhra Pradesh, which rises to 1,690 meters.
- A Broken, Discontinuous Chain: The most defining characteristic of the Eastern Ghats is that they are not a continuous range. Over millions of years, mighty east-flowing peninsular rivers like the Godavari, Krishna, Mahanadi, and Kaveri have violently sliced through these mountains, breaking them into isolated hills and sprawling deltas.
- Local Nomenclatures: Because of this high degree of fragmentation, the Eastern Ghats are known by various local names in different states. In Andhra Pradesh, they form the Nallamala and Palkonda ranges, while in Tamil Nadu, they are known as the Javadi, Shevaroy, and Pachaimalai hills.
π Physical Geography β’ Geomorphology
Q.10) The Geosynclinal Origin theory suggests that the disintegration of Pangaea about 200 million years ago led to the formation of the Tethys Sea. Who among the following were the main supporters of this theory?
Ans > (B) Argand, Kober and Suess
- Explanation: The main supporters of the geosynclinal origin of the Himalayas are Argand, Kober and Suess.
- The Geosynclinal Theory Concept: Before the modern theory of Plate Tectonics became widely accepted, the Geosynclinal theory was the leading explanation for mountain building (orogeny). It proposed that vast, shallow marine depressions called geosynclines filled with massive amounts of sediment, which eventually buckled under pressure to form mountains.
- The Role of the Tethys Sea: According to Kober, Argand, and Suess, the Tethys Sea acted as a massive geosyncline positioned between two ancient landmasses: Angaraland (Eurasia) to the north and Gondwanaland (India) to the south. Over millions of years, rivers deposited thousands of meters of sediment into this shallow sea.
- Compressional Forces: Kober argued that as the Earth cooled, the rigid forelands (Angaraland and Gondwanaland) moved closer together, exerting immense lateral compressional forces. This immense pressure squeezed the soft, accumulated Tethys sediments upward, folding them into the towering ranges of the Himalayas.
- Modern Scientific Context: While the Geosynclinal theory successfully explained the presence of marine sedimentary rock at the top of the Himalayas, it has largely been superseded by modern Plate Tectonics (championed by Hess and Morgan). Plate tectonics provides a more accurate mechanism for how the continental plates actually moved and collided.
π Physical Geography β’ Plate Tectonics
Q.11) According to the Plate Tectonic theory of the Himalayas, the first major phase of uplift initially produced which of the following mountain ranges before the formation of the Great Himalayas?
Ans > (B) Ladakh and Zaskar ranges
- Explanation: It is believed that the first major phase of uplift initially produced the Ladakh and Zaskar ranges of the Trans-Himalayas before the formation of the Great Himalayas.
- The Continental Collision: According to Plate Tectonic theory, the Himalayas were formed by a violent continental collision. As the Indian Plate drifted rapidly northward and collided with the static Eurasian Plate, the intervening Tethys Sea was closed, and the crust began to buckle and fold upward.
- The Sequence of Upliftment: This collision was not a single, instantaneous event. The tectonic crushing happened in distinct phases. The very first compressional phase occurred over 50 million years ago, leading to the initial buckling of the earth’s crust at the exact zone of collision.
- Formation of the Trans-Himalayas: The immense pressure from this initial impact resulted in the upliftment of the Ladakh and Zaskar ranges. Because these ranges formed first, they sit just north of the Great Himalayas and are geologically classified as part of the Trans-Himalayan zone.
- Subsequent Formations: It was only after this initial Trans-Himalayan uplift that continued tectonic pressure forced the creation of the Great Himalayas (the tallest and central axis) during a second phase, followed millions of years later by the Lesser Himalayas and finally the Shiwaliks.
π Indian Geography β’ Trans-Himalayas
Q.12) The Trans-Himalayas contain Tethys marine sediments and constitute the core of the Himalayan axis. What is the approximate width of this physiographic division?
Ans > (B) 40 km
- Explanation: The Trans-Himalayas are about 40 km wide. They contain the Tethys sediments.
- Location and Extent: The Trans-Himalayan region, also frequently referred to as the Tibetan Himalayas, lies immediately to the north of the Great Himalayan range. This zone spans approximately 1,000 kilometers in length east-to-west, serving as the physical transition zone between the Indian subcontinent and the Tibetan Plateau.
- Geographical Width: The average width of this rugged, high-altitude physiographic division is approximately 40 kilometers. Despite being relatively narrow compared to the overall Himalayan system, it contains some of the most formidable and remote terrain on the planet, including the Karakoram, Ladakh, and Zaskar sub-ranges.
- Marine Geological Evidence: A defining geological feature of the Trans-Himalayas is the massive presence of marine sedimentary rock, including limestones and shales containing ancient marine fossils (like ammonites). This serves as absolute proof that this high-altitude region was once the floor of the prehistoric Tethys Sea.
- Ecological Characteristics: Because the towering Great Himalayas block the moisture-laden monsoon winds from the south, the 40-km wide Trans-Himalayan zone exists in an extreme rain shadow. As a result, it is characterized by arid, high-altitude cold deserts, devoid of dense vegetation, similar to the landscape of Ladakh.
π Indian Geography β’ Mountain Peaks
Q.13) Situated on the border of Sikkim and Tibet, Kanchenjunga is the third highest mountain peak in the world. What is its exact elevation above sea level?
Ans > (C) 8,598 m
- Explanation: Kanchenjunga: Situated on the border of Sikkim and Tibet, it is the third highest mountain peak in the world. It is 8,598 metres above sea level. (Note: Standard older geography texts use 8,598m; modern satellite surveys generally list it as 8,586m).
- Global Ranking and Location: Kanchenjunga is a colossal mountain massif located in the Eastern Himalayas. It stands proudly on the international border separating the Indian state of Sikkim and eastern Nepal. It is the highest peak in India and the third highest in the world, surpassed only by Mount Everest and K2.
- The Five Treasures: The name “Kangchenjunga” translates from Tibetan as “The Five Treasures of the High Snow.” This refers to the massif’s five distinct, towering peaks, four of which exceed 8,450 meters. The “treasures” are said to represent salt, gold, turquoise, sacred scriptures, and invincible armor.
- Cultural Reverence: The mountain holds immense spiritual significance for the indigenous Lepcha people and the broader population of Sikkim, who view it as a sacred guardian deity. Out of respect for these local religious beliefs, early mountaineering expeditions (and many modern ones) intentionally stopped just short of the actual summit to avoid defiling it.
- Ecological Significance: The Kanchenjunga massif is surrounded by the Khangchendzonga National Park, a UNESCO World Heritage site. Because of the massive elevational gradients, the region boasts incredible biodiversity, ranging from subtropical forests at its base to alpine shrubs and permanent glaciers near its peaks.
π Indian Geography β’ Mountain Passes
Q.14) Which important mountain pass, constructed by the Border Road Organisation (BRO), connects the Kullu valley with the Lahul and Spiti valleys in Himachal Pradesh?
Ans > (B) Rohtang Pass
- Explanation: Rohtang Pass: Located at an elevation of 3979 m above sea level, this pass connects the Kullu, the Lahul and Spiti valleys of Himachal Pradesh.
- Strategic Geographical Location: Rohtang Pass is situated in the eastern Pir Panjal Range of the Himalayas, approximately 51 kilometers from the popular hill station of Manali. Sitting at an elevation of 3,979 meters (13,054 ft), it acts as a crucial natural gateway separating two very distinct geographic zones.
- A Climatic Divide: The pass is a literal dividing line between two contrasting climates. To the south lies the Kullu Valley, characterized by lush, green, monsoon-fed forests and heavy rainfall. To the north lie the Lahaul and Spiti Valleys, which exist in a high-altitude, arid, cold-desert rain shadow.
- Historical Treachery: The name “Rohtang” roughly translates to “pile of corpses” in the local Tibetan-origin dialects. This grim name reflects the historical dangers of crossing the pass, which is notorious for sudden, unpredictable snowstorms, vicious blizzards, and treacherous road conditions that historically claimed many lives.
- Modern Infrastructure and the Atal Tunnel: Because heavy snow historically closed the pass for six months every year, the Indian government constructed the Atal Tunnel beneath it. Opened in 2020, this 9.02 km tunnel allows year-round military and civilian connectivity to Lahaul and Spiti, dramatically altering regional logistics.
π Indian Geography β’ High Altitude Passes
Q.15) Located at an elevation of 5359 m above sea level, which pass is recognized as the second highest motorable mountain pass in India after Khardung La?
Ans > (C) Thang La
- Explanation: Thang La (Ladakh): Located at an elevation of 5359 m above sea level, it is a mountain pass in Ladakh (J & K). It is the second highest motorable mountain pass in India after Khardung La.
- Position on the Leh-Manali Highway: Thang La (more commonly spelled Tanglang La) is a major high-altitude mountain pass in the Union Territory of Ladakh. It is a critical waypoint on the grueling 428-kilometer Leh-Manali Highway, heavily utilized by the military and adventure tourists.
- Extreme Altitude Challenges: Situated at an oxygen-deprived elevation of 5,359 meters (17,582 feet), the pass tests the endurance of both vehicles and humans. Travelers passing through Thang La frequently experience symptoms of Acute Mountain Sickness (AMS) due to the thin air and biting cold, even during the summer months.
- Geological Surroundings: The pass is nestled within the Zanskar Range of the Trans-Himalayas. The landscape surrounding Thang La is incredibly desolate, characterized by barren, wind-swept scree slopes, devoid of permanent vegetation, offering a stark, rugged beauty typical of the Ladakh cold desert.
- Modern Survey Context: It is important to note that while classic geography curricula cite Khardung La and Thang La as the highest, modern GPS measurements and recent infrastructural developments by the Border Roads Organisation (BRO) have crowned new records. Umling La in eastern Ladakh is now the worldβs highest motorable pass at 5,798 meters (19,024 ft).
π Indian Geography β’ Glaciology
Q.16) The altitude of the snowline varies across the Himalayas depending on latitude, moisture, and local topography. What is the general altitude of the snowline in the Kashmir Himalayas?
Ans > (B) 5100 m to 5800 m
- Explanation: The altitude of the snowline in the Kashmir Himalayas varies between 5100 m to 5800 m.
- Understanding the Snowline: The snowline is the exact boundary or elevation above which snow and ice remain on the ground continuously throughout the year, never completely melting even during the peak of summer. It is a critical metric for studying glaciers and mountain hydrology.
- Variables Affecting the Altitude: The height of the snowline is not uniform. It depends heavily on two main factors: latitude (distance from the equator) and precipitation. A region that receives massive amounts of winter snow will have a lower snowline than a dry region at the exact same latitude.
- The Kashmir Himalayas Context: In the Kashmir Himalayas (located in the western section of the mountain range), the climate is drier compared to the Eastern Himalayas. Because there is less overall moisture and less heavy snowfall, the snowline sits higher, generally varying between 5,100 to 5,800 meters.
- Eastern vs. Western Discrepancy: In stark contrast, the Eastern Himalayas (like Sikkim and Arunachal Pradesh) receive immense amounts of precipitation from the Southwest Monsoon. This heavy moisture supply causes the snowline in the east to be significantly lower (around 4,300 meters) despite being closer to the equator.
π Indian Geography β’ River Basins
Q.17) River basins in India are classified into three categories based on their catchment area. A “medium basin” is defined as having a catchment area of:
Ans > (B) Between 2,000 to 20,000 sq km
- Explanation: The river basins of India have been classified into three categories: river basins having a catchment area between 2000 to 20,000 sq km known as the medium basins.
- Catchment Area Definition: A river basin (or catchment area) is the entire geographical land area from which water naturally flows and drains into a single, common river system. It includes the main river and all its associated tributaries and sub-tributaries from their source to the sea.
- The Three-Tier Classification: The Ministry of Water Resources in India officially categorizes river basins into three tiers for better administrative and hydrological management: Major (or Large) basins, Medium basins, and Minor basins, based purely on the square kilometer area they drain.
- Characteristics of Medium Basins: A medium river basin is strictly defined as having a catchment area spanning between 2,000 and 20,000 square kilometers. There are 44 identified medium river basins in India, representing a vital but secondary layer of the nation’s surface water resources.
- Common Locations: Most medium river basins in India do not originate in the high Himalayas. Instead, they are typically found in the Peninsular plateau and along the coastal plains. Common examples include the fast-flowing, shorter rivers of the Western Ghats (like the Periyar or Netravati) and smaller east-flowing rivers like the Subarnarekha.
π Indian Geography β’ Major Rivers
Q.18) Out of the total one hundred and thirteen river basins recorded in India, how many are officially classified as “large” river basins?
Ans > (A) 14
- Explanation: India has one hundred and thirteen river basins, of which 14 are large, 44 medium and 55 minor river basins.
- Definition of a Large Basin: According to Indian hydrological classifications, a “large” or “major” river basin is defined as having a massive catchment area that exceeds 20,000 square kilometers. These systems represent the primary arteries of India’s geography.
- The 14 Major Arteries: India features exactly 14 such major river basins. This elite list includes colossal Himalayan systems like the Ganga, Brahmaputra, and Indus, as well as massive peninsular systems such as the Godavari, Krishna, Mahanadi, Narmada, Kaveri, and Tapi.
- Economic and Agricultural Dominance: While they number only 14 out of 113 total basins, these large basins are overwhelmingly dominant. They account for nearly 85% of India’s total surface water runoff and house the vast majority of the nation’s population, agriculture, and major hydroelectric dams.
- Geopolitical and Interstate Friction: Because these large basins span thousands of kilometers and cross multiple state (and international) boundaries, they are frequently the centers of intense water-sharing disputes. Examples include the ongoing Kaveri river water dispute between Karnataka and Tamil Nadu, and the Indus Water Treaty with Pakistan.
π Indian Geography β’ River Origins
Q.19) The Yamuna River is the longest and the western-most tributary of the Ganga. From which glacier does it originate?
Ans > (C) Yamunotri Glacier
- Explanation: The Yamuna River (length 1380 km)… Its source lies in the Yamunotri Glacier on the western slopes of Banderpunch (6316 m).
- Origin and Source Elevation: The Yamuna River originates from the pristine Yamunotri Glacier, which is located at an impressive elevation of approximately 6,316 meters (20,720 ft). This glacier sits on the southwestern slopes of the Banderpunch massif in the Uttarkashi district of Uttarakhand.
- Course and Length: Stretching for roughly 1,380 kilometers, the Yamuna is not just the longest tributary of the Ganga, but also the second-largest tributary river in India overall. It flows through the Himalayan foothills before entering the plains, carving a parallel path to the Ganga.
- The Ganga-Yamuna Doab: As the Yamuna flows southeast parallel to the Ganga, the fertile land situated directly between these two mighty rivers is known as the Ganga-Yamuna Doab. This exceptionally fertile alluvial tract is one of the most densely populated and agriculturally productive regions in the world.
- Major Tributaries and Confluence: The Yamuna is heavily augmented by several large right-bank peninsular tributaries originating from the Malwa Plateau, including the Chambal, Betwa, and Ken. It ultimately merges with the Ganga River at the sacred Triveni Sangam in Prayagraj (Allahabad), marking one of Hinduism’s holiest sites.
π Indian Geography β’ Waterfalls
Q.20) The Narmada River, which flows through a complex rift valley course, forms a spectacular 10-metre high waterfall near Jabalpur known as:
Ans > (C) Dhuandhar Waterfalls
- Explanation: Moving north-westward, it passes through a complex course near Jabalpur, through some impressive marble gorges, the most spectacular being Dhunwadhar Waterfalls (10m high) near Jabalpur.
- The Rift Valley Mechanism: The Narmada River is structurally unique among India’s major rivers. Instead of flowing through a self-carved valley, it flows westward through a massive geological fault lineβa rift valleyβsituated between the Vindhya mountain range to the north and the Satpura range to the south.
- The Bhedaghat Marble Gorges: Before creating the waterfall, the Narmada flows through Bhedaghat near Jabalpur, Madhya Pradesh. Here, the river has carved a breathtaking gorge through towering cliffs of pure white and colored magnesium limestone, famously known as the Marble Rocks, rising up to 100 feet high.
- Mechanics of Dhuandhar: As the river exits this narrow marble gorge, the channel suddenly drops, creating the Dhuandhar Falls. The name literally translates to “Smoke Cascade” (Dhuan = smoke, Dhar = flow) because the force of the water plunging creates a massive, permanent mist that resembles rising smoke.
- Ecological and Tourism Significance: Beyond its geological wonder, the Dhuandhar falls and the surrounding Bhedaghat gorge are major tourist attractions. The powerful flow of the Narmada here is also indicative of the river’s massive kinetic energy, which is harnessed further downstream by major hydroelectric projects like the Sardar Sarovar Dam.
π Geomorphology β’ River Piracy
Q.21) River capturing in the geological past had severe consequences for early settlements. The upper course of the ancient Saraswati River was captured by a tributary of which major river system, eventually giving birth to the Yamuna River?
Ans > (B) Ganga System
- Explanation: Later on, the water of its upper course was captured by a tributary of the Ganga River as a result of which its lower course became dry. This gave birth to Yamuna River, an important tributary of the Ganga System.
- The Phenomenon of River Piracy: “River capturing” or “river piracy” is a fascinating geomorphological event. It occurs when a river with a steeper gradient or stronger erosive power violently cuts backward (headward erosion) into an adjacent valley, intersecting and “stealing” the water from another, slower-flowing river.
- The Fate of the Saraswati: The ancient, mythological Saraswati River is believed by many geologists to have been a massive, thriving river system that flowed through present-day Haryana and Rajasthan. However, tectonic upheavals in the Himalayas drastically altered the landscape, initiating a catastrophic series of river captures.
- Birth of the Yamuna: Tectonic tilting caused a tributary of the rapidly expanding Ganga system to capture the upper glacial sources of the Saraswati. This captured water was diverted eastwards, eventually evolving into the modern Yamuna River, which now faithfully feeds the Ganga.
- The Drying of the West: Simultaneously, tectonic shifts forced the Sutlej River (which also fed the Saraswati) to shift westward and join the Indus system. Stripped of its two massive glacial water sources, the mighty Saraswati was reduced to the seasonal, rain-fed Ghaggar-Hakra channel, severely impacting the ancient Harappan civilizations that lived on its banks.
π Indian Geography β’ Lakes
Q.22) Renuka Lake, which features a Lion Safari and a zoo, is a major attraction that hosts an annual fair in the month of November. In which state is it situated?
Ans > (C) Himachal Pradesh
- Explanation: Situated in the Sirmour District of Himachal Pradesh, this lake has been named after the goddess Renuka. A Lion Safari and a zoo are major attractions at Renuka.
- Geographic Positioning: Renuka Lake is situated in the Sirmaur district of Himachal Pradesh. Resting at an altitude of 672 meters above sea level, it holds the title of the largest natural lake in the state of Himachal Pradesh, boasting a circumference of approximately 3.2 kilometers.
- Mythological Significance: The lake is shaped like the profile of a reclining woman. According to Hindu mythology, it is the embodiment of Goddess Renuka, the mother of Lord Parshuram (the sixth avatar of Vishnu). A smaller, adjacent lake represents her son. This mythology makes it a massive pilgrimage site.
- Ecological Status (Ramsar Site): Because of its rich biodiversity and importance as a freshwater ecosystem, Renuka Lake was designated as a Ramsar Wetland of International Importance in 2005. It supports various species of migratory birds, fish, and aquatic flora, necessitating strict environmental protections.
- Tourism and Conservation: The area is a major tourism hub, augmented by a Lion Safari and a mini-zoo on its banks. However, the lake faces severe ecological threats from heavy siltation, untreated sewage from surrounding tourist facilities, and eutrophication (excessive weed growth), prompting ongoing state conservation efforts.
π Indian Geography β’ Glacial Lakes
Q.23) Radio-carbon dating suggests that people died in an epidemic around which high-altitude lake in Uttarakhand, where 600 skeletons were discovered in 1942?
Ans > (B) Roopkund
- Explanation: Situated in Uttarakhand, it is a lake around which 600 skeletons were found at the edge of the lake. The location is uninhabited and is located at an altitude of about 5080 m. The skeletons were discovered in 1942. (Note: While early theories suggested an epidemic, modern consensus points to a severe hailstorm).
- The “Skeleton Lake”: Roopkund is a high-altitude glacial tarn located at a staggering elevation of 5,029 meters (16,499 feet) in the Garhwal Himalayas of Uttarakhand. Nestled deep within the Nanda Devi National Park, it remains frozen for most of the year, revealing its macabre contents only during the brief summer thaw.
- The 1942 Discovery: The lake gained international infamy in 1942 when a British forest guard, H.K. Madhwal, stumbled upon the frozen lake surrounded by hundreds of human skeletons. Initially, British authorities feared the remains belonged to a secret Japanese invasion force attempting to cross the Himalayas during WWII.
- Scientific Revelations: Subsequent radio-carbon dating and extensive DNA analysis dismantled the WWII theory. The skeletons are much older, dating back to roughly the 9th century CE. Furthermore, paleogenomic studies revealed that the dead were of diverse origins, including a group of local Indian pilgrims and a separate group with Mediterranean ancestry.
- The Cause of Death: While early theories suggested an epidemic or a battle, modern forensic analysis of the skulls provides a clearer picture. Many skulls feature unhealed, localized fractures from above. The scientific consensus is that a group of pilgrims was caught in an incredibly violent and sudden hailstorm, battered to death by cricket-ball-sized hailstones with nowhere to hide.
π Indian Geography β’ Islands
Q.24) The Nicobar group of islands comprise a total of 18 islands. Out of these, exactly how many are inhabited?
Ans > (C) 11
- Explanation: The Nicobar group of islands comprise 18 islands of which only 11 are inhabited.
- The Nicobar Archipelago: The Nicobar Islands represent the southern segment of the Andaman and Nicobar Union Territory, separated from the northern Andaman group by the deep and turbulent Ten Degree Channel. The archipelago spans roughly 262 miles of ocean space in the Bay of Bengal.
- Demographic Isolation: Of the traditionally recognized 18 main islands in the Nicobar group, only 11 are inhabited. This deliberate lack of widespread habitation is heavily tied to strict Indian government policies aimed at protecting the ecologically fragile environment and the vulnerable indigenous populations.
- Indigenous Tribes: The inhabited islands are home to two primary indigenous tribes. The Nicobarese, who are relatively assimilated and primarily inhabit Car Nicobar, and the highly reclusive Shompen tribe, a semi-nomadic hunter-gatherer group residing strictly within the dense rainforests of Great Nicobar Island.
- The Tsunami Impact: The geography and demographics of the Nicobar islands were drastically altered by the catastrophic 2004 Indian Ocean Earthquake and Tsunami. The islands suffered direct hits, resulting in massive loss of life, the complete destruction of several coastal villages, and permanent geological subsidence of certain islands.
π Indian Agriculture β’ Andaman & Nicobar
Q.25) What is the primary agricultural crop cultivated in the Andaman and Nicobar Islands?
Ans > (A) Rice
- Explanation: Rice is the main crop in Andaman and Nicobar Islands.
- Climatic Suitability: The Andaman and Nicobar Islands experience a hot, humid, tropical equatorial climate characterized by heavy rainfall brought by both the Southwest and Northeast monsoons. These wet, humid conditions are perfectly tailored for the cultivation of paddy (rice).
- Limited Arable Land: Despite rice being the primary staple crop, agriculture on the islands is heavily restricted. Over 80% of the Union Territory is covered by dense, protected tropical rainforests. Consequently, arable land is extremely scarce and largely confined to narrow coastal strips and cleared valleys.
- Agricultural Challenges: Island farmers face unique challenges. The soil, while fertile in pockets, is prone to rapid leaching due to heavy rains. Furthermore, following the 2004 tsunami, vast tracts of coastal agricultural land suffered from severe saltwater intrusion, rendering them temporarily or permanently unfit for rice cultivation.
- Shift Towards Plantation Crops: Because large-scale grain farming is unsustainable on the islands, the local agricultural economy relies heavily on plantation and cash crops. Alongside rice for subsistence, farmers extensively cultivate coconut, arecanut (betel nut), rubber, and tropical spices like cloves and nutmeg on the hill slopes.
π Climatology β’ Pressure Systems
Q.26) During the winter season in the Northern Hemisphere, strong high-pressure areas develop over the Asian landmass. Along with Peshawar in Pakistan, where does another significant high-pressure area develop?
Ans > (C) Baikal Lake (Siberia)
- Explanation: Contrary to this, in the Northern Hemisphere during winter season, there develops high pressure areas near Baikal Lake (Siberia), and Peshawar (Pakistan).
- The Siberian High: The phenomenon in question is meteorologically known as the “Siberian High” or “Siberian Anticyclone.” During the Northern Hemisphere winter, the massive, uninterrupted landmass of Eurasia cools rapidly and intensely. This extreme cold causes the air to become incredibly dense, creating a massive zone of high atmospheric pressure.
- Core Centering: This massive, sprawling high-pressure system typically centers itself near Lake Baikal in Siberia, Russia. It is one of the strongest semi-permanent high-pressure centers in the Northern Hemisphere, often dictating the winter weather patterns for millions of square miles across Asia.
- Outward Wind Flow: In meteorology, air flows from high pressure to low pressure. Therefore, the Siberian High generates freezing, dry, outward-flowing winds that sweep southward and eastward across the Asian continent, plunging temperatures in regions like China, Korea, and Japan.
- India’s Geographic Shield: India is largely protected from these freezing Siberian winds by the towering wall of the Great Himalayas. The mountains physically block the cold air from entering the subcontinent. However, the pressure gradient still drives the Northeast Trade Winds, which pick up moisture over the Bay of Bengal to bring winter rain to India’s Coromandel Coast.
π Climatology β’ Indian Monsoon
Q.27) During the active “break monsoon” conditions, a low valley trough develops over the Assam Plain, aligning along the river Brahmaputra. What is the specific vertical extent of this low valley trough?
Ans > (B) 2 to 3 kilometres
- Explanation: The vertical extent of this low valley trough is 2 to 3 kilometres with the south-west Monsoon lying to the south of the trough, remaining independent of the main monsoon trough.
- Understanding the Monsoon Trough: During the Indian Summer Monsoon, an elongated zone of low atmospheric pressure develops across northern India, known as the Monsoon Trough. The position of this trough dictates where heavy rainfall occurs. Normally, it stretches from Rajasthan down to the Bay of Bengal.
- The “Break” Phenomenon: A “break in the monsoon” occurs when this trough abruptly shifts far northward from its normal position, relocating to the foothills of the Himalayas. During this period, rainfall practically ceases over the core agricultural plains of central and peninsular India.
- The Assam Valley Trough: When the trough shifts to the Himalayan foothills, a specific, shallow low-pressure valley trough develops over the Assam Plain, running parallel to the Brahmaputra River. This localized meteorological feature is relatively shallow, with a vertical atmospheric extent of only 2 to 3 kilometers.
- Impact on the Northeast: While central India suffers a dry spell, this 2-3 km high trough traps immense moisture against the mountains. This results in torrential, concentrated downpours in the Northeast states (like Assam) and the sub-Himalayan regions, frequently leading to devastating floods in the Brahmaputra valley.
π Indian Flora β’ Forests
Q.28) Tropical Moist Deciduous forests are the typical monsoon forests of India. What is the scientific botanical name for Teak, one of the dominant species in these forests?
Ans > (B) Tectona grandis
- Explanation: These are typical monsoon forests with teak (Tectona grandis) and sal (Shorea robusta) as the dominant species.
- The “Monsoon Forests”: Tropical Moist Deciduous forests are the most widespread forest type in India. They thrive in regions receiving moderate to heavy rainfall, typically between 100 to 200 centimeters annually. Because they shed their leaves during the dry spring and early summer to conserve water, they are commonly called “Monsoon Forests.”
- Tectona Grandis Characteristics: The scientific name for Teak is Tectona grandis. It is a towering, broad-leaved hardwood tree renowned globally for its incredible durability, rich golden-brown color, and natural oils that make it highly resistant to termites, rot, and water damage.
- Geographical Distribution: In India, natural Teak forests are largely confined to the central and southern regions. They flourish extensively in the undulating terrains of Madhya Pradesh, Maharashtra, Karnataka, and Kerala, particularly on the lower, well-drained slopes of the Western Ghats.
- Economic Exploitation: Because of its immense value in premium furniture making, shipbuilding, and luxury construction, Teak (along with Sal, Shorea robusta) has been heavily logged. Today, due to severe depletion of natural stands, the Indian government strictly regulates teak harvesting and aggressively promotes state-run teak plantations.
π Indian Flora β’ Himalayan Vegetation
Q.29) The Deodar tree produces wood that is light brown to yellow in colour, sturdy, and highly durable. In the north-western Himalayas, it primarily thrives between the heights of:
Ans > (C) 1500 m and 2500 m
- Explanation: Deodar (Cedrus Deodara) grows in the north-western Himalayas… between the heights of 1500 m and 2500 m.
- Altitudinal Forest Zones: Vegetation in the Himalayas is dictated not just by latitude, but heavily by altitude. As one ascends the mountains, tropical forests quickly give way to subtropical, temperate, and eventually alpine vegetation. The Deodar cedar is a hallmark species of the Himalayan Temperate zone.
- The Domain of the Deodar: The Deodar (Cedrus deodara) specifically thrives in the cooler, drier north-western Himalayas (Jammu & Kashmir, Himachal Pradesh, and Uttarakhand). It is heavily concentrated at elevations ranging between 1,500 and 2,500 meters, where it experiences cold winters and moderate snowfall.
- Wood Characteristics and Mythology: The word “Deodar” translates from Sanskrit as “Timber of the Gods” (Deva = god, Daru = wood). The tree yields a highly aromatic, yellow-to-brown softwood that is incredibly durable and naturally resistant to pests, making it deeply revered in local cultures and temple architecture.
- Commercial and Ecological Value: Historically, the sturdy, straight trunks of the Deodar were heavily exploited by the British to manufacture railway sleepers to expand India’s train network. Ecologically, the massive root systems of these towering cedars are vital for stabilizing steep mountain slopes and preventing catastrophic landslides.
π Indian Flora β’ High Altitude Conifers
Q.30) Found in the north-western and north-eastern Himalayas, the Silver-fir (Abies) tree provides soft but not very durable wood. Which of the following is it predominantly used for?
Ans > (C) Planking, packing boxes, wood-pulp, and match sticks
- Explanation: It is found in the north-western and north-eastern Himalayas… The wood is soft but not very durable. It is mostly used for planking, packing boxes, containers, wood-pulp, paper, and match sticks.
- High-Altitude Conifers: The Silver-fir (genus Abies) is an evergreen coniferous tree that grows at even higher altitudes than the Deodar. It forms the upper canopy of the Himalayan moist temperate and sub-alpine forests, typically thriving between 2,500 and 3,500 meters, thriving in regions with heavy winter snow.
- Softwood Characteristics: Unlike the heavy, dense, and rot-resistant hardwoods found in the lower plains (like Teak or Sal), the Silver-fir produces classic “softwood.” This timber is very light, easy to cut, and lacks the natural resins that provide long-term durability against weather and insects.
- Industrial Applications: Because it cannot be used for heavy structural engineering or outdoor furniture, Silver-fir wood is utilized for rapid industrial consumables. Its lightness and fibrous structure make it perfect for manufacturing packing crates, matchsticks, and crucially, for being mashed down into wood-pulp for the paper industry.
- Environmental Impact: The demand for cheap softwood for packaging and paper has led to significant commercial logging in these fragile high-altitude ecosystems. Because these alpine environments have very short growing seasons, a logged Silver-fir forest takes many decades to recover, raising major concerns about deforestation near the snowline.
π Quick Summary β Geography Set 14
- Himalayan Upheaval: The 3rd major upheaval occurred during the Post-Pliocene Period.
- Quaternary Glaciation: Ice-sheets descended to 1500 metres in India.
- Peninsular Plateau: The general elevation ranges between 600β900 metres.
- Malwa Drainage: The Mahi river drains towards the Arabian Sea.
- Meghalaya Plateau: Nokrek is the highest peak of the Garo Hills.
- Dandakaranya: Primarily drained by the Sabari and Sileru (Godavari tributaries).
- Karnataka Plateau: The Nandi valley is a famous summer resort in the Maidan region.
- Western Ghats: The Palakkad Gap (Palghat) is approximately 24 km wide.
- Eastern Ghats: Highly detached with an average elevation of 600 m.
- Geosynclinal Theory: Supported by Argand, Kober, and Suess regarding Tethys Sea.
- Plate Tectonics: The first Himalayan uplift phase produced the Ladakh and Zaskar ranges.
- Trans-Himalayas: This Tethys sediment zone is approximately 40 km wide.
- Kanchenjunga: The third highest peak in the world stands at 8,598 m.
- Mountain Passes: Rohtang Pass connects Kullu with Lahul and Spiti.
- High Altitude Passes: Thang La is the second highest motorable pass (5359 m).
- Kashmir Himalayas: The snowline varies between 5100 m to 5800 m.
- River Basins: Medium basins have a catchment area of 2,000 to 20,000 sq km.
- Major Rivers: India has 14 officially classified “large” river basins.
- Yamuna River: Originates from the Yamunotri Glacier on Banderpunch.
- Narmada River: Forms the spectacular 10m high Dhuandhar Waterfalls near Jabalpur.
- River Piracy: The Ganga System captured the upper ancient Saraswati River.
- Lakes: Renuka Lake, featuring a Lion Safari, is in Himachal Pradesh.
- Glacial Lakes: Roopkund (Skeleton Lake) is located in Uttarakhand.
- Nicobar Islands: Out of 18 main islands, 11 are inhabited.
- Andaman Agriculture: Rice is the primary agricultural crop cultivated.
- Climatology: A major winter high-pressure area develops over Baikal Lake (Siberia).
- Indian Monsoon: The Assam low valley trough extends 2 to 3 kilometres vertically.
- Monsoon Forests: Tectona grandis is the scientific name for Teak.
- Himalayan Vegetation: Deodar trees thrive between 1500 m and 2500 m.
- High Altitude Conifers: Silver-fir wood is used for planking, packing boxes, and match sticks.
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