Geography: UPSC Previous Year Questions (Prelims)

Explanation

Option (a) is correct: The Congo Basin is a vast region in Central Africa, encompassing approximately 3.7 million square kilometers. It spans across several countries, including Cameroon, the Central African Republic, the Democratic Republic of the Congo, the Republic of the Congo, Equatorial Guinea, and Gabon. It is home to the Congo Rainforest which is the second-largest tropical rainforest globally, after the Amazon. This region plays a crucial role in climate regulation, carbon storage, and biodiversity conservation. Cameroon forms the northwestern boundary of the Congo Basin. The southeastern parts of Cameroon--especially the regions of East, South, and Centre provinces--are covered by dense equatorial rainforests that are part of the basin.

Option (b),(c) and (d) are incorrect:

Nigeria is located further west. Nigeria’s terrain is dominated by savannah, mangroves, and rainforests but it is located outside the Congo Basin. South Sudan is rich in wetlands (Sudd Swamp) but it lies northeast of the Congo Basin and is part of the Nile Basin. Uganda shares a border with the Democratic Republic of the Congo but it belongs to the Great Lakes Region and Nile River Basin and not the Congo Basin.

Explanation

Statement 1 is incorrect: Low, thick clouds, not the high clouds primarily reflect solar radiation and cool the surface of the Earth.

Statement 2 is incorrect: High, thin clouds, not the low clouds primarily transmit incoming solar radiation. At the same time, they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface of the Earth.

Explanation

Option (c) is correct: The Tea Board under the Ministry of Commerce and Industry, along with the Indian Tea Association, lists Assam, West Bengal, Tamil Nadu, Himachal Pradesh, Tripura, Kerala, and Karnataka as tea-producing States. Kerala: Known for its tea plantations, particularly in Wayanad and the Western Ghats. Himachal Pradesh: Known for tea cultivation, especially in Kangra region. Tripura: Also a tea-producing State, with significant tea cultivation. Andhra Pradesh: Not a tea-producing State compared to the others listed. However, some claim Araku Valley as a minor tea production centre in the state. India tea production during 2023-24 was 1382.03 Million Kgs increased by 7.06 Million Kgs over 2022-23

Explanation

Statement 1 and 2 are correct: In India, monazite serves as the primary source of rare earth elements and thorium. Rare earth metals comprise a group of 17 elements known for their lustrous, silvery-white appearance and soft, heavy metallic properties. China dominates global rare earth production, contributing around 60-70 % of the total output. These elements play a critical role in the production of electronics, magnets, and batteries. Monazite, abundant in India’s coastal sands, is rich in rare earth elements and thorium, a radioactive material. Thorium is crucial for India’s three stage nuclear energy program.

Statement 3 is incorrect: Monazite is not found in the entire Indian coastal sands. While it is found along most of the southern Indian coast, particularly in Kerala, Tamil Nadu, and Orissa, it does not occur throughout the entire coastline.

Statement 4 is correct: As per Atomic Energy (Radiation Protection) Rules 2004, Indian Rare Earths Limited (IREL), a wholly owned Public Sector Undertaking of the Government of India (GOI) under Department of Atomic Energy (DAE), is the only entity which has been permitted to produce and process monazite, and handle it for domestic use as well as for export. Fig: Rare Earth Minerals

Explanation

Option (c) is correct: Gandikota canyon is situated on the Pennar River in Andhra Pradesh and is known as the Grand Canyon of India. Gandikota is a small village in the Kadapa district of Andhra Pradesh. Gorges are formed when rivers erode through gigantic rock formations over a long period of time. A gorge is any valley formed by a source of water flowing between tall slabs of steep rocks. The swift flowing waters of River Pennar cut through the granite rocks near the village of Gandikota, naturally eroding the rock and forming a deep valley.

Explanation

Pair 1 is incorrectly matched: Namcha Barwa is not situated in Garhwal Himalayas. It is part of Eastern Himalayas marking the easternmost section of the Himalayas. The peak lies inside the Great Bend of the Yarlung Tsangpo River, where the river takes a significant turn before entering India as the Brahmaputra.

Pair 2 is correctly matched: The part of the Himalayas lying between Satluj and Kali rivers is known as Kumaon Himalayas. Nanda Devi is part of the Kumaon Himalayas located in the Chamoli district of Uttarakhand. The peak is flanked by the Rishi-ganga valley to the west and the Goriganga valley to the east. The surrounding Nanda Devi National Park was recognized for its unique biodiversity and was declared a UNESCO World Heritage Site.

Pair 3 is incorrectly matched: Nokrek Peak stands as the high-est point in Meghalaya’s Garo Hills, situated in northeastern In-dia. It belongs to the Shillong Plateau and is geographically separate from the Sikkim Himalaya which is located further north in Sikkim. It is recognized for its diverse flora and fauna and the Nokrek region has been designated a UNESCO Biosphere Re-serve.

Explanation

Pair 1 is incorrectly matched: The Ghataprabha Reservoir is built on the Ghataprabha River, a tributary of the Krishna River, located in the Belagavi district of Karnataka(not Telengana). It provides irrigation to the drought-prone regions of north Karnataka. The Gokak Falls is located on this river.

Pair 2 is correctly matched: The Gandhi Sagar Dam is constructed on the Chambal River is situated in the Mandsaur and Neemuch districts of Madhya Pradesh. It is one of the five major dams of the Chambal Valley Project and plays a vital role in irrigation and hydroelectricity.

Pair 3 is incorrectly matched: The Indira Sagar Dam is the largest dam in India, in terms of volume of water stored in the reservoir. It is located in Madhya Pradesh, not Andhra Pradesh. It is built on the Narmada River and is one of the largest reservoirs in India.

Pair 4 is incorrectly matched: The Maithon Dam is built on the Barakar River, a tributary of the Damodar River. It is situated in Dhanbad district of Jharkhand. It is a key component of the Damodar Valley Corporation (DVC) project, controlling floods and generating hydroelectric power.

Explanation

Option (a) is incorrect: Lake Victoria, located in East Africa (Kenya, Uganda, Tanzania), is the largest lake in Africa. It remains full and functional, supporting millions of people and diverse ecosystems.

Option (b) is correct: Lake Faguibine in Mali, West Africa, has mostly dried up due to climate change, low rainfall, and human activities. It was once one of the largest lakes in West Africa, covering 590 km², but has shrunk since the 1970s due to severe droughts. The lake depends on seasonal flooding from the Niger River, but with less water, the area has turned into dry land. This has badly affected farming, fishing, and the livelihoods of people who relied on the lake.

Option (c) is incorrect: Lake Oguta, located in Nigeria, is a permanent freshwater lake. It has not dried up and continues to serve as an important water source for local communities.

Option (d) is incorrect: Lake Volta, located in Ghana, is one of the largest artificial reservoirs in the world. It was created by the construction of the Akosombo Dam on the Volta River. The lake remains full and continues to be a vital source of hydroelectric power, irrigation, and fishing.

Explanation

Statement 1 is correct: In the tropical zone, trade winds blow from the east towards the west. These winds push warm surface water towards the western parts of the oceans (e.g., the western Pacific Ocean and the western Atlantic Ocean). As a result, the water in the western parts of tropical oceans is warmer than in the eastern parts. The eastern sections of the oceans tend to have upwelling, where colder, nutrient-rich waters from deeper layers rise to the surface.

Statement 2 is correct: In the temperate zone, the westerlies (winds blowing from the west towards the east) push the surface water eastward, causing the western parts of oceans (like the western coast of continents) to be colder. The water in the eastern sections of oceans tends to be warmer due to the Ekman transport, which moves warm water towards the eastern coasts. For example, in the North Atlantic Ocean, the Gulf Stream carries warm water from the tropics to the eastern coasts of North America and Europe, keeping the eastern sections warmer than the western parts.

Explanation

Option (d) is correct: The description refers to the Tropical Rainforest or Hot, Wet Equatorial Climate. In this biome, leaf litter decomposes rapidly due to high humidity and temperatures, quickly returning nutrients to the soil. As a result, the soil surface often appears bare with minimal leaf litter. They are home to climbing plants (lianas) and epiphytes (plants that grow on trees), which reach the canopy to access sunlight. These unique plant forms and rapid decomposition are characteristic features of tropical rainforests, making it a highly dynamic and nutrient-efficient ecosystem. Options (a), (b) and (c) are incorrect:

Coniferous forests (or taiga) are characterized by cold climates and slow decomposition rates. The leaf litter in coniferous forests decomposes more slowly than in tropical rainforests due to the lower temperatures and acidic nature of the soil. The description of rapid decomposition and bare soil does not match the characteristics of coniferous forests. Dry deciduous forests experience dry seasons where many trees shed their leaves. While leaf litter does decompose, the process is slower due to the dry conditions. These forests do not have the constant, year-round decomposition found in tropical rainforests. Additionally, the mention of epiphytes and climbing plants is less common in dry deciduous forests. Mangrove forests are coastal ecosystems, typically found in tropical and subtropical regions. They are characterized by salt-tolerant plants and the intertidal zone, not by the rapid de-composition of leaf litter. The soil in mangrove forests is often muddy, and the vegetation is adapted to waterlogged conditions rather than the "bare" soil and climbing plants described in the given statement.