UPSC Prelims Previous Year Questions 2020: Environment | Environment for UPSC CSE PDF Download

Ans: (d)

• Benzene (C₆H₆) is a colorless, flammable liquid with a sweet odor. It evaporates quickly when exposed to air. Benzene is formed from natural processes, such as volcanoes and forest fires, but most of the exposure to benzene results from human activities.
• The main sources of benzene in the environment include automobile exhaust, industrial sources, and fuel evaporation from gasoline filling stations. Hence, statement 1 is correct.
• Benzene has been detected at high levels in indoor air. Although some of this exposure might be from building materials (paints, adhesives, etc.), most is from cigarette smoke. Hence, statement 2 and 4 are correct.

Therefore, option (d) is the correct answer.

Ans: (c)

• The practice of supplying crops in the field with fertilizers via the irrigation water is called fertigation. It is a modern agro-technique that facilitates higher yield and reduced environmental pollution by increasing fertilizer use efficiency, minimizing fertilizer application and increasing return on the fertilizer invested.
• The benefits of fertigation methods over conventional or drop-fertilizing methods include:
  • Increased nutrient absorption by plants.
  • Accurate placement of nutrient, where the water goes the nutrient goes as well. Ability to ‘microdose’, feeding the plants just enough so nutrients can be absorbed and are not left to be washed down to stormwater next time it rains.
  • Reduction of fertilizer, chemicals, and water needed. Reduced leaching of chemicals into the water supply.
  • Reduced water consumption due to the plant’s increased root mass’s ability to trap and hold water.
  • Application of nutrients can be controlled at the precise time and rate necessary. Minimized risk of the roots contracting soil borne diseases through the contaminated soil.
  • Reduction of soil erosion issues as the nutrients are pumped through the water drip system. Leaching is decreased often through methods used to employ fertigation.
  • Through fertigation, pH of the irrigation water can be managed.
• Fertigation method is not advisable in agriculture if the substance used can form precipitate and Phosphate may form precipitate in water having high Calcium and Magnesium content. Hence, statement 2 is not correct.

Therefore, option (c) is the correct answer.

Ans: (c)

• The Desert National Park (DNP), an area of 3162 km², spreads over districts of Jaisalmer and Barmer in Rajasthan. The area falls in the extreme hot and arid region of very low rainfall zone (<100 mm) of the country. DNB was demarcated and notified in 1980. Hence, statement 1 is correct.
• The Thar desert is the most thickly populated desert in the world with an average density of 83 persons/ km². However, the human population within the DNP is low (4-5 persons per km²). There are around 70 villages and also settlements or Dhanis existing within the Park. Hence, statement 2 is not correct.
• The Thar desert harbours a wide array of flora and faunal species. It is the only place where Rajasthan State Bird (Great Indian Bustard) are found naturally. Hence, statement 3 is correct.

Therefore, option (c) is the correct answer.

Ans: (b)

• Based on groundwater levels, areas across the country are split into three categories: Over-exploited, Critical and Semi critical. The first refers to groundwater being extracted more than what’s recharged i.e. extraction is more than 100%. Critical where the groundwater taken out is 90-100% of what’s recharged and semi- critical where extraction rate is 70%-90%.
• As per the report ‘National Compilation on Dynamic Groundwater Resources of India, 2017’ of CGWA, out of the total 6881 assessment units (Blocks/Mandals/ Talukas) in the country, 1186 units in various States (17%) have been categorized as ‘Over- Exploited’, 313 units (5%) are ‘Critical’, and 972 are semi-critical units (14%). Hence, statement 1 is not correct.
• The Central Ground Water Authority (CGWA) was constituted under Section 3(3) of the Environment (Protection) Act, 1986 to regulate, control development and management of ground water resources. Hence, statement 2 is correct.
• As per report of Food and Agriculture Organization (FAO) of UN, the countries with the largest extent of areas equipped for irrigation with groundwater, in absolute terms, are India (39 million ha), China (19 million ha) and the USA (17 million ha). Hence, statement 3 is correct.

Therefore, option (b) is the correct answer.

Ans: (c)

• Critical Tiger Habitats (CTH), also known as core areas of tiger reserves, are identified under the Wild Life Protection Act, 1972 based on scientific evidence that “such areas are required to be kept as inviolative for the purpose of tiger conservation, without affecting the rights of the Scheduled Tribes or such other forest dwellers”.
• The CTHs are notified by the state government in consultation with the expert committee constituted for the purpose.
• Area of the core/critical tiger habitat:
  • Corbett (Uttarakhand): 821.99 sq. kms 
  • Ranthambore (Rajasthan): 1113.36 sq. kms 
  • Sundarbans (West Bengal): 1699.62 sq. kms
  • Nagarjunsagar Srisailam (part of Andhra Pradesh): 2595.72 sq. kms

Therefore, option (c) is the correct answer.

Ans: (a)

• The Wild Life Protection Act, 1972 is enacted for protection of plants and animal species. The Act provides for the protection of wild animals, birds and plants. It has six schedules which give varying degrees of protection.
• Schedule I and part II of Schedule II provide absolute protection - offences under these are prescribed the highest penalties.
• Species listed in Schedule III and Schedule IV are also protected, but the penalties are much lower.
• Schedule V includes the animals which may be hunted.
• The specified endemic plants in Schedule VI are prohibited from cultivation and planting.
• In Schedule VI, following plants are included:
  • Beddomes’ cycad (Cycas beddomei), 
  • Blue Vanda (Vanda soerulec),
  • Kuth (Saussurea lappa),
  • Ladies slipper orchids (Paphiopedilum spp.), 
  • Pitcher plant (Nepenthes khasiana),
  • Red Vanda (Rananthera imschootiana)
• However, the further also states that cultivation of specified plants without licence is prohibited. As per Section 17C of the Act, no person shall cultivate a specified plant except under and in accordance with a licence granted by the Chief Wild Life Warden or any other officer authorised by the State Government in this behalf.

Therefore, option (a) is the correct answer.

Ans: (a)

• The social cost of carbon (SCC) is an estimate, in dollars, of the economic damages that would result from emitting one additional ton of greenhouse gases into the atmosphere.
• The SCC puts the effects of climate change into economic terms to help policymakers and other decision makers understand the economic impacts of decisions that would increase or decrease emissions.
• India’s country-level social cost of carbon emission was estimated to be the highest at $86 per tonne of CO₂. It means the Indian economy will lose $86 by emitting each additional tonne of CO₂. India is followed by the US ($48) and Saudi Arabia ($47).

Therefore, option (a) is the correct answer.

Ans: (a)

• The elephant herd is led by the oldest and largest female member (known as the matriarch). This herd includes the daughters of the matriarch and their offspring. Hence, statement 1 is correct.
• Elephants have the longest-known gestational (pregnancy) period of all mammals, lasting up to 680 days (22 months). Hence, statement 2 is correct.
• Females between 14 - 45 years may give birth to calves approximately every four years with the mean interbirth intervals increasing to five years by age 52 and six years by age 60. Hence, statement 3 is not correct.
• As per Elephant Census (2017), Karnataka has the highest number of elephants (6,049), followed by Assam (5,719) and Kerala (3,054). Hence, statement 4 is not correct.

Therefore, option (a) is the correct answer.

Ans: (c)
Nagarhole National Park:

• This park is also known as Rajiv Gandhi National Park. It is located in the two districts of Karnataka, namely Mysore and Kodagu.
• The park was established as a wildlife sanctuary in 1955 and was upgraded into a national park in 1988.
• The park was declared as the 37th Tiger reserve in 1999.
• Kabini, a tributary of the Cauvery River, is the largest river draining the park.

Hence, option 1 is correct.

Papikonda National Park:

• This park is spread over 1012.86 square kilometres in East and West Godavari districts of Andhra Pradesh.
• It has historically experienced varying levels of protection, beginning as a reserve
• forest in 1882, a wildlife sanctuary in 1978, and as a national park from 2008. The park lies along the left and right banks of the river Godavari and cuts through the Papikonda hill range of Eastern Ghats.

Hence, option 2 is not correct.

Sathyamangalam Tiger Reserve:

• Sathyamangalam Wildlife Sanctuary and Tiger Reserve is a protected area and tiger reserve along the Western Ghats in the Erode district of the state of Tamil Nadu.
• In the northern part of Erode district, Palar river flows and drains into Cauvery river.

Hence, option 3 is correct.

Wayanad Wildlife Sanctuary:

• Located in Kerala, Wayanad Wildlife Sanctuary (WWS) is an integral part of the Nilgiri Biosphere Reserve. It was established in 1973.
• It is contiguous to the tiger reserves of Nagerhole and Bandipur of Karnataka and
• Mudumalai of Tamil Nadu.
• Kabini river (a tributary of Cauvery river) flows through the sanctuary.

Hence, option 4 is correct.
Therefore, option (c) is the correct answer.

Ans: (a)
These all are part of the Avian ecology.

Ceylon frogmouth:

• It is a grey-brown nocturnal bird species that is found in the Western Ghats and Sri Lanka’s forested habitats.
• It is distinguished by its wide, hooked bill with slit-like nostrils and a large head
• with eyes facing forward.
• With destruction of forest cover, this species is likely compelled to now take refuge in cashew plantations.

Coppersmith barbet:

• Also called crimson-breasted barbet and coppersmith, it is an Asian barbet with crimson forehead and throat, known for its metronomic call that sounds similar to a coppersmith striking metal with a hammer.
• It is a resident bird in the Indian subcontinent and parts of Southeast Asia.

White-throated Redstart:

• It is a species of bird in the Muscicapidae family.
• It is found in Bhutan, China, India, Myanmar, and Nepal.

Grey-Chinned Minivet:

• It is a species of bird in the Campephagidae family.
• It is found in Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Taiwan, Thailand and Vietnam.
• Its natural habitat is subtropical or tropical moist lowland forests.

Therefore, option (a) is the correct answer.

Ans: (a)

• Hard ground swamp deer or Barasingha (Rucervus duvaucelii), the state animal of Madhya Pradesh, is seeing a revival in the Kanha National Park and Tiger Reserve (KNPTR).
• Swamp Deer was close to extinction in the Kanha National Park. However, with the conservation efforts, the population currently numbers around 800.
• The deer is endemic to the Kanha National Park and Tiger Reserve on the Maikal Range of Satpura Hills. Measures like captive breeding and habitat improvement were used.

Therefore, option (a) is the correct answer.

Ans: (a)

• Musk deer live mainly in forested and alpine scrub habitats in the mountains of southern Asia, notably the Himalayas.
• Askot Wildlife Sanctuary:
  • It is located 54 km from Pithoragarh, near Askot in Uttarakhand state of India. 
  • This sanctuary has been set up primarily with the object of conserving the musk deer and its habitat. Hence, 1 is correct.
• Gangotri National Park:
  • Established in 1989, it is located in the upper catchment of Bhagirathi River in Uttarakhand.
  • The park is home to blue sheep, Himalayan Tahr, musk deer, snow leopard etc. Hence, 2 is correct.
• Kishanpur Wildlife Sanctuary:
  • It is a part of the Dudhwa Tiger Reserve near Mailani in Uttar Pradesh. It was founded in 1972.
  • In this sanctuary, tiger, chital, hog deer, wild boars, otters, and many more animals find themselves a home.
  • A huge number of resident and migratory birds like falcons, drongos, owls, egrets, and peacocks can be spotted in the open meadows, which is traversed by perennial streams. Hence, 3 is not correct.
• Manas National Park:
  • Manas National Park is located in the Himalayan foothills in Assam. It is contiguous with the Royal Manas National Park in Bhutan.
  • It is known for its rare and endangered endemic wildlife such as the Assam
  • roofed turtle, hispid hare, golden langur and pygmy hog.
  • Manas is famous for its population of the wild water buffalo. Hence, 4 is not correct.

Therefore, option (a) is the correct answer.

Ans: (a) 

• Copper slag is a by-product obtained during smelting and refining of copper. The waste copper slag can be used as abrasive tools, road construction, and ballast. The use of copper slag in cement and concrete provides potential environmental as well as economic benefits for all related industries, particularly in areas where a considerable amount of copper slag is produced. Hence, 1 is correct.
• Cold mix asphalt is produced by mixing unheated mineral aggregate with either emulsified bitumen or foamed bitumen. Cold asphalt mixes are typically suitable for light to medium trafficked roads when used in base and surface courses. Hence, 2 is correct.
• Geotextile is a synthetic permeable textile material used to improve the soil characteristics and has the ability to separate, filter, reinforce, protect and drain when used in association with soils. It is mostly used for filtration and separation in the road constructions. Hence, 3 is correct.
• Hot Mix Asphalt (HMA) is a combination of approximately 95% stone, sand, or gravel bound together by asphalt cement, a product of crude oil. The wide use of hot mix technology leads to environmental pollution as these plants emit a huge amount of greenhouse gases. Hence, 4 is not correct.
• Portland cement is a binding material in the formof a finely ground powder, that is manufactured by burning and grinding a mixture of limestone and clay. Its production generates greenhouse gases. Hence, 5 is not correct.

Therefore, option (a) is the correct answer.

Ans: (d)

• Coal ash, also referred to as coal combustion residuals or CCRs, is produced primarily from the burning of coal in coal-fired power plants. It contains contaminants like mercury, cadmium and arsenic. Without proper management, these contaminants can pollute waterways, ground water, drinking water, and the air. Hence, statement 1 is correct.
• Coal based thermal power plants are major source of Sulphur dioxide and Nitrogen oxides emissions. Hence, statement 2 is correct.
• According to Coal India Limited, the ash content of coal produced in the country is generally 25 to 45% whereas average ash content of imported coal varies from 10 to 20%. Hence, statement 3 is correct.

Therefore, option (d) is the correct answer.

Ans: (d)

• Biochar is a porous carbonaceous solid produced by heating various biomass feedstocks under high temperatures in an oxygen-limited environment.
• As biochar migrates vertically through the soil profile, therefore can be used as a part of the growing medium in vertical farming. Hence, statement 1 is correct.
• Due to its adsorption ability, some biochars have the potential to immobilise heavy metals, pesticides, herbicides, and hormones; prevent nitrate leaching and faecal bacteria into waterways; and reduce N₂O and CH₄ emissions from soils. Hence, statement 2 is correct.
• Biochar can help retain water and nutrients in the soil for the plants to take up as they grow. Hence, statement 3 is correct.

Therefore, option (d) is the correct answer.