Geography: UPSC Previous Year Questions (Prelims)

Explanation

The exceptionally high population densities in both the Nile Valley and the island of Java are primarily attributable to the practice of intensive agriculture. The fertile soil, favorable climate, and availability of water have made these regions ideal for farming, which has historically supported large populations. Industrialization and urbanization are secondary factors, while topographic limitations have influenced but not caused the high population density. Region Key Natural Factor Primary Agricultural Practice Resulting Population Density Nile Valley Nutrient-rich silt from annual Nile floods Intensive cultivation of wheat, rice, cotton Sustained high density in a narrow fertile strip Java Fertile volcanic soil Intensive rice cultivation Among the high-est population densities globally

Explanation

The Mekong-Ganga Cooperation (MGC) is a regional initiative aimed at enhancing cultural, economic, and tourism ties among member countries. It was launched in 2000 and includes six countries: India, Thailand, Myanmar, Cambodia, Laos, and Vietnam. The project focuses on areas such as tourism, education, culture, and transportation, rather than irrigation, hydroelectric power, or defense.

Explanation

Assertion (A) is true: Anticyclonic conditions are characterized by high atmospheric pressure and sinking air, which leads to clear skies and low temperatures. These conditions are com-mon in winter, especially in northern India after a cyclonic rain from western disturbances. Reason (R) is true: Winter rainfall in northern India, such as the Western Disturbances, is the result of cyclonic (low-pressure) conditions. However, this rain also creates conditions of anticyclonic activity. R correctly explains A: Cyclonic activities beyond the Indian border bring rain to India in winter. This creates a high Pressure area with light winds radiating outwards. This wind creates anticyclonic activity in northern India. Thus, Reason (R) is the correct explanation of Assertion (A).

Explanation

Statement 1 is correct: As of 2001, India’s total installed power generation capacity was approximately 95,000 MW, according to reports from the Central Electricity Authority (CEA). This included contributions from thermal, hydroelectric, nuclear, and renewable energy sources. As of June 2023-24, the installed capacity has risen to around 146,190 MW.

Statement 2 is incorrect: As of 2001 and even today, nuclear power contributes only around 1-3% (not 15%) of the total electricity generation. The installed nuclear capacity is approximately 7,480 MW, which is a minor fraction of the total energy mix. India’s nuclear expansion has been slow due to regulatory challenges, safety concerns, and the high cost of nuclear plants.

Statement 3 is incorrect: Hydroelectricity accounted for about 25-30% of India’s electricity generation in 2001, not 40%. While hydroelectricity was once a dominant source of power in India, its share has been gradually declining as thermal and renewable energy sources expanded. Currently, hydroelectricity accounts for only about 10-15% of India’s total power generation.

Statement 4 is incorrect: In 2001, thermal power plants (coal, oil, and natural gas) contributed about 65-70% of India’s total power generation, not 80%. Thermal power remains the back-bone of India’s energy sector but has never accounted for such a high percentage. Currently, thermal power contributes around 70-75% of total power generation. While close to 80%, the exact figure fluc-tuates due to the increasing contribution of renewable energy sources like solar and wind.

Explanation

The Aravalli Range, one of the world’s oldest mountain systems, is estimated to be around 670 million years old based on geological studies and radiometric dating techniques. Some researchers even suggest its origins could date back further, making it as old as 2-4 billion years, but its prominent development and erosion cycles place its approximate age at 670 million years.

Explanation

Statement 1 is correct: The Gulf of Mannar Biosphere Reserve, located between India and Sri Lanka, is one of India’s 18 biosphere reserves. Established in 1989, it is the first marine biosphere reserve in South and Southeast Asia. Known for its rich marine biodiversity, especially coral reefs, it supports over 1,10,000 families from 268 fishing villages. It also lies along the Central Asian bird migratory flyway.

Statement 2 is correct: The Ganga Action Plan (GAP) Phase II, launched in 1993, aimed to expand pollution control efforts to the Ganga’s tributaries. In 1995, it was merged with the National River Conservation Plan (NRCP) to include other polluted rivers across India. The NRCP focused on sewage treatment, riverfront development, afforestation, and pollution control in 190 towns across 16 states. Later, in 2014, the Namami Gange Programme was launched to further strengthen Ganga rejuvenation efforts.

Statement 3 is correct: The National Museum of Natural History, opened in 1978, in New Delhi plays a significant role in promoting environmental education and awareness. It offers various programs, exhibitions, and activities to impart non-for-mal education on environment and conservation.

Statement 4 is correct: ENVIS (Environmental Information System) was launched in 1982 by the Ministry of Environment, Forest and Climate Change (MoEFCC) as a decentralized system for collecting and disseminating environmental information across various thematic areas.

Explanation

If an observer sees the stars rising perpendicular to the horizon, they are positioned at the equator. At the Earth’s equator, stars appear to rise straight up from the eastern horizon, move directly overhead, and set in the west. This occurs because the Earth’s rotational axis is perpendicular to the observer’s horizon at this location. The celestial equator, which is an imaginary extension of Earth’s equator into space, perfectly aligns with the observer’s horizon. As a result, stars follow a vertical trajectory as they rise and set. In contrast, at other latitudes, such as the Tropic of Cancer, the North Pole, or the South Pole, stars rise and set at different angles due to the observer’s varying position on the globe and the tilt of the Earth.

Explanation

Option (b) is correct: Australia is home to a wide variety of marsupials, including kangaroos, koalas, wombats, and tasmanian devils. About 70% of all marsupial species are found in Australia. Options (a), (c) and (d) are incorrect:

South America does have a few marsupials, such as the opossum, but the diversity and number of marsupial species are far greater in Australia. Africa, and South East Asia do not have significant populations of marsupials. Marsupials are rare or absent in these regions.

Explanation

A is correctly matched with 4: The Fohn is a warm, dry, downslope wind that occurs in the Alps. It’s a katabatic wind, meaning it’s created by air descending from a higher elevation. As air is forced up the windward side of a mountain range, it cools and condenses, losing its moisture as precipitation. The now dry air continues over the mountain crest and descends on the leeward side. As it descends, it compresses and warms, often significantly. This results in a sudden rise in temperature and a decrease in humidity on the leeward side, creating the characteristic Fohn wind. These winds can have a significant impact on local weather, causing rapid snowmelt, increasing the risk of avalanches, and even influencing vegetation patterns. B is correctly matched with 2: The Sarmun is a hot, dry, and dusty wind that blows in the Kurdistan region, particularly in northern Iraq and parts of Iran. It’s a type of desert wind, of-ten associated with low-pressure systems. These winds can carry large amounts of dust and sand, reducing visibility and causing discomfort. They are most common during the summer months and can lead to significant temperature increases and dry conditions, impacting agriculture and water resources. The Sarmun is similar to other regional desert winds like the Khamsin in Egypt or the Sirocco in the Mediterranean, although its specific characteristics and regional impact are unique to the Kurdistan area. C is correctly matched with 3: The Santa Ana winds are strong, dry, and warm winds that blow in Southern California. They originate from high-pressure systems over the Great Basin region and flow southwestward towards the coast. As the air descends from the higher elevations of the mountains surrounding Southern California, it compresses and warms, becoming very dry. These winds are channeled through canyons and mountain passes, increasing their speed and intensity. Santa Ana winds are known for their ability to rapidly increase fire danger, as they create extremely dry conditions and can quickly spread wildfires. They are most common in the fall and winter months and can also cause power outages and damage to property. D is correctly matched with 1: The Zonda is a dry and dusty wind that affects the western slopes of the Andes Mountains in Argentina. Similar to the Fohn, it’s a katabatic wind. Moist air is forced up the eastern slopes of the Andes, where it cools and releases its moisture. The dry air then descends on the western side, warming as it compresses. The Zonda is characterized by its hot and dry nature, often carrying dust and sand from the high-altitude deserts. It can cause significant temperature fluctuations and reduce visibility. These winds are most prevalent during the winter months and can have a significant impact on agriculture and local weather patterns in the affected regions of Argentina.

Explanation

The Roaring Forties are strong westerly winds found between 40° and 50° latitudes in the Southern Hemisphere, known for their strength due to the absence of major landmasses.

Statement 1 is incorrect: These winds are exclusive to the Southern Hemisphere, as large landmasses in the Northern Hemisphere disrupt wind flow.

Statement 2 is correct: The Roaring Forties are driven by strong pressure gradients between the subtropical high-pres-sure belt and subpolar low-pressure zone, with the Southern Hemisphere’s vast oceans enhancing their consistency.

Statement 3 is correct: The Coriolis effect causes a deflection of these winds, giving them a north-west to east trajectory.

Statement 4 is correct: These winds carry moisture, often resulting in stormy, rainy conditions, especially in the Southern Indian and Pacific Oceans.