Geography: UPSC Previous Year Questions (Prelims)

Explanation

Assertion (A) is true: Mangroves are specialised for-est ecosystems found in the tropical and subtropical regions of the world especially along coastlines where saltwater and freshwater meet. They are specially adapted to thrive in saline, waterlogged soils where few other plants can survive. Reason (R) is true: Mangroves play a critical role in stabilizing shorelines by trapping sediments with their dense root systems, reducing erosion, and protecting coastal areas from storm surges and sea-level rise. They act as natural barriers, mitigating the impact of waves and tides, and preventing seawater from en-croaching further inland. Reason (R) correctly explains Assertion (A): Assertion (A) describes mangroves as specialized ecosystems in tropical and subtropical coastal regions and Reason (R) explains why these ecosystems are specialized i.e. their ability to stabilize shorelines and protect against sea encroachment.

Explanation

Manganese, Nickel, Lead-zinc, and Asbestos are important mineral resources in India, each predominantly mined in specific states due to favorable geological conditions. A is correctly matched with 1: Manganese ore is a crucial raw material for the steel industry and is extensively mined in Madhya Pradesh. Regions like the Balaghat district in Madhya Pradesh are well known for their significant deposits. B is correctly matched with 2: Nickel is primarily mined in Orissa (Odisha), where substantial reserves exist, particularly in areas such as the Sukinda Valley. Orissa is recognized for its notable nickel deposits. C is correctly matched with 3: Lead and zinc ores are largely found in Rajasthan. The Zawar mines in are one of the most prominent sources of lead and zinc in India. Rajasthan is renowned for its lead-zinc mining. Lead and Zinc are used in batteries, galvanization, and alloys. D is correctly matched with 4: Asbestos is mined in Andhra Pradesh, particularly in regions like Cuddapah and Kurnool. Andhra Pradesh has well-established asbestos mining operations. They are used for roofing sheets, insulation, and fire-proof materials.

Explanation

Cotton Production in India is concentrated in regions with warm temperatures (21-30°C), a semi-arid climate, and soil conditions favorable to cotton cultivation (such as the black, moisture-retaining regur soil). It is produced in North-west and Western India in states like Gujarat, Maharashtra, and Punjab. Gujarat: Recognized as the largest cotton producer in India, owing to its conducive climate and extensive cultivation practices. Maharashtra: Known for significant rainfed cotton farming on regur soil, which supports high yields. Rajasthan: Especially in its irrigated parts, Rajasthan contributes a substantial share to the country’s cotton production

Explanation

Population density is measured as the number of people per square kilometer, is a key demographic indicator. It reflects the distribution of population across regions and is influenced by geographical, economic, and social factors.

Option (a) is correct: The following table presents the approximate population densities (in persons per square kilometer) for the four states across three Census years:

State Census 1991 Census 2001 Census 2011 Sikkim 57 76 86 Nagaland 73 119 120 Meghalaya 79 115 132 Manipur 82 98 122 In 1991, Sikkim had a population density of 57 persons/km², which was lower than Nagaland (73), Meghalaya (79), and Manipur (82). Its mountainous terrain and limited habitable land contribute to sparse population distribution. In contrast, Nagaland, Meghalaya, and Manipur had higher densities due to more favorable living conditions and agricultural practices.

Explanation

India has diverse agro-climatic zones, enabling different regions to specialize in certain crops based on soil type, rainfall, and climate.

Pair 1 is incorrectly matched: Tapioca (cassava) is widely grown in Kerala, particularly in hilly and rainfed areas, but it is not considered a major or economically significant crop of the state compared to others.

Pair 2 is correctly matched: Maharashtra is a leading producer of cotton in India, particularly in Vidarbha and Marathwada regions, owing to its black soil. Maharashtra is followed by Gujarat and Telangana in cotton production.

Pair 3 is correctly matched: West Bengal is the largest producer of jute in India, contributing around 75% of the nation’s total yield. The benefits from the alluvial soils of the Ganga-Brahmaputra delta and experienced agricultural workforce. Known for its durability and versatility, jute plays a crucial role in various industries, including textiles and packaging.

Pair 4 is correctly matched: Gujarat leads in groundnut production, especially in Saurashtra and Kutch regions, due to suitable sandy loam soils and semi-arid conditions. Alongwith suitable soil type and favourable climatic conditions, application of advance farming techniques helps Gujarat produce the largest share of country’s groundnut yield.

Explanation

Wheat is mainly grown during Rabi season and has wide adaptability. It can be grown not only in the tropical and sub-tropical zones, but also in the temperate zone and the cold tracts of the far north, beyond even to the 60 degrees North altitude.

Option (a) is correct: Wheat grows best in a moderate temperature range of 10°C-25°C. For a good crop of wheat, the following conditions are ideal:

Temperature: Wheat grows best in a moderate temperature range of 10°C-25°C. Temperatures above 25 C during this period tend to depress grain weight. Moderate rainfall of 50-75 cm is sufficient, as excessive rainfall can damage the crop. Cloudy weather, with high humidity and low temperatures is conducive for rust attack Wheat requires a cool climate during the growing period and a warm, dry climate during harvesting to ensure proper grain development.

Explanation

The Barak Valley is located in the southern part of Assam, India, comprising the districts of Cachar, Karimganj, and Hailakandi. This region is characterized by a warm and humid climate, with temperatures ranging from 25°C to 30°C and annual rainfall between 100 to 200 cm. These conditions are ideal for the cultivation of jute, making it a significant crop in the Barak Valley.

Option (a) is correct: Jute is grown here as a cash crop and contributes significantly to the region’s agricultural economy. Jute flourishes in regions with high humidity, temperatures exceeding 25°C, and well-drained loamy soil. The Barak Valley is enriched by the Barak River which provides these ideal conditions making it highly suitable for jute cultivation. Options (b), (c) and (d) are incorrect:

While tea is a significant crop in Assam, tea cultivation is more prominent in the Brahmaputra Valley rather than the Barak Valley. Sugarcane is cultivated in various parts of India, including Assam but it is not a major crop of the Barak Valley. The major sugarcane producing states in India are Uttar Pradesh, Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh, Gujarat, Bihar, Haryana, Punjab, and Odisha with Uttar Pradesh being the largest producer of sugarcane in the country. Cotton is not a significant crop in the Barak Valley due to the region’s unsuitable climatic and soil conditions. States of India known for cotton production include Gujarat, Maharashtra, Telangana, Andhra Pradesh, and Madhya Pradesh.

Explanation

During summer, high temperatures over the Indian sub-continent cause low pressure to develop, leading to a northward shift of the Intertropical Convergence Zone (ITCZ), especially in the northern regions. This low-pressure system draws moist air from the Indian Ocean, resulting in the arrival of southwest monsoon winds that bring rainfall to the subcontinent.

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

The south-east monsoon originates in the Southern Hemisphere and moves from the high-pressure areas in the south-east towards the low-pressure regions in the subcontinent. However, this is not the primary wind pattern responsible for bringing the summer rains, as it is the south-west monsoon that is more prominent. Trade winds blow from the east and are associated with the tropical regions, but they don’t bring the monsoon rains to India. They primarily affect the equatorial regions. The westerlies are winds that blow from the west and generally affect the higher latitudes of the mid-latitudes. They are not responsible for the monsoon system in India.

Explanation

The Western Ghats of India are considered an ecological hotspot due to their exceptional biodiversity and the large number of species that are found nowhere else in the world (endemism). The region is home to several unique ecosystems, including tropical rainforests, grasslands, and wetlands, and supports an array of plant and animal species, many of which are endangered.

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

The Himalayas, both Western and Eastern, are vital for biodiversity; however, they are not as prominently recognized as biodiversity hotspots compared to regions like the Western Ghats. The Eastern Ghats are ecologically important but do not meet the criteria of an "ecological hotspot" when compared to regions like the Western Ghats or the Eastern Himalayas. While they host a diverse set of species, they lack the same degree of endemism and are not as internationally recognized for biodiversity.

Explanation

The term ‘De-notified Tribes’ (DNTs) refers to communities that were previously classified as ‘Criminal Tribes’ under the Criminal Tribes Act (CTA) of 1871 during British rule in India. The British labeled certain nomadic and semi-no-madic tribes as ‘criminal’ by birth based on their traditional livelihoods, often involving hunting, trading, or performing arts. After India’s independence, the Criminal Tribes Act was repealed in 1952, and these communities were ‘denotified’, meaning they were no longer considered criminal by default. However, despite this legal change, many Denotified Tribes (DNTs) and Nomadic Tribes (NTs) continue to face social stigma, discrimination, and lack of formal recognition.