UPSC Prelims 2020 Analysis

Explanation

The term 'Social Cost of Carbon' is a measure of the economic damages, in dollars, that would result from emitting one additional ton of carbon dioxide into the atmosphere.

It is used to value the climate impacts of rulemakings and helps policymakers understand the economic impacts of decisions that would increase or decrease emissions.

Therefore, it is best described as the long-term damage done by a tonne of carbon dioxide emissions in a given year.

Explanation

Nagarhole National Park is located in the Kodagu and Mysore districts of Karnataka and is part of the Nilgiri Biosphere Reserve. It is indeed located in the Cauvery basin.

Papikonda National Park is not located in the Cauvery basin. It is actually located in the Godavari basin.

Sathyamangalam Tiger Reserve lies on the banks of the River Bhavani, a tributary of the River Cauvery in the foothills of the Eastern Ghats. So, it is located in the Cauvery basin.

Wayanad Wildlife Sanctuary: The Kabini river, a tributary of the Cauvery river, flows through the Wayanad Wildlife Sanctuary. Hence, it is also located in the Cauvery basin.

So, the correct answer includes Nagarhole National Park, Sathyamangalam Tiger Reserve, and Wayanad Wildlife Sanctuary.

Explanation

Southern swamp deer/ hard ground swamp deer, a unique sub-species of Barasingha, also known as the Indian swamp deer, is a herbivorous species that feeds exclusively on grasses (graminivorous) and is well adapted to is adapted to hard ground in open sal forest.

Kanha National Park is well-known for the conservation of hard ground swamp deer. Conservation efforts by the park have helped revive its numbers from near extinction.

Therefore, the correct answer is Kanha National Park.

Explanation

Benzene is a colorless or light yellow liquid at room temperature and is a well-known environmental pollutant. It is widely present in the environment due to various natural and human-made sources..

Automobiles, especially those running on petrol, are a significant source of benzene pollution. Since benzene is a component of petroleum products, including motor fuels, its combustion in vehicle engines releases benzene into the air, contributing significantly to air pollution.

Tobacco smoke is a source of benzene exposure. Both active smoking and passive smoking introduce benzene into the body, as tobacco smoke contains benzene. Prolonged exposure to such smoke increases health risks.

Wood burning releases benzene and other pollutants like polycyclic aromatic hydrocarbons (PAHs) due to incomplete combustion. Hence, wood burning is a source of benzene pollution.

Varnished wooden furniture can be a source of benzene exposure but it is less direct and typically with lower exposure levels once the varnish has cured. Therefore, it is not considered a significant source of benzene pollution.

Polyurethane-based products do not contribute significantly to benzene pollution. They are more associated with volatile organic compounds (VOCs) and other chemicals rather than benzene itself.

Thus, the major contributors to benzene pollution are automobile emissions, tobacco smoke, and wood burning . Hence the correct answer is A. 1, 2 and 3 only.

Explanation

Biochar is a solid product obtained during the pyrolysis of biomass. It is a porous, carbon-rich material that has a wide range of uses, with soil improvement, remediation, and pollution control playing the most significant roles. In agriculture, biochar is primarily used to increase crop nutrition, plant growth, and soil fertility.

Statement 1 is correct. Biochar can indeed be used as a part of the growing medium in vertical farming. It helps in improving the soil structure and fertility, thereby promoting plant growth.

Statement 2 is correct. Biochar promotes the growth of nitrogen-fixing microorganisms. These microorganisms play a crucial role in the nitrogen cycle by converting atmospheric nitrogen into a form that plants can use.

Statement 3 is correct. Biochar also enables the growing medium to retain water for a longer time. Its porous nature allows it to hold onto water and nutrients, making them readily available for plant roots.

Therefore, all the three statements are correct.

Explanation

Eco-friendly agriculture refers to farming practices that are sustainable and cause minimal harm to the environment.

Crop diversification is one such practice. It involves growing a variety of crops in the same area over different seasons. This method enhances soil health, reduces the need for excessive water and fertilizers, and boosts biodiversity in the ecosystem. By rotating crops, it also helps in preventing soil depletion and improves resilience against pests and diseases.

Legume intensification is another eco-friendly practice. Legumes are known to improve soil fertility by fixing nitrogen from the atmosphere. This reduces the need for synthetic fertilizers, making agriculture more sustainable.

Tensiometer is a useful tool in efficient water management. It measures the water tension in soil, which helps in determining the availability of water for crops. By ensuring that water is used efficiently, it reduces waste and promotes sustainable water usage, making it an eco-friendly farming practice.

Vertical farming involves growing crops in vertically stacked layers, often using advanced techniques like hydroponics, aeroponics, and aquaponics, which do not require soil. While this method can increase production and reduce land usage, it requires high energy consumption and specialized technology. Hence, it is not widely considered as an eco-friendly practice.

Therefore, the correct answer is A. 1, 2, and 3 only.

Explanation

Statement 1 is correct: Fertigation is a method of delivering fertilizers to crops through an irrigation system. It involves the precise application of water-soluble or liquid fertilizers directly to the root zone of plants during the irrigation process. This technique allows for the controlled release of nutrients, ensuring that plants receive the right amount at the right time. Fertigation allows for the control of the pH of the irrigation water, which can be adjusted to the optimal level for nutrient absorption by the plants.

Statement 2 is incorrect: While fertigation does allow for the efficient application of many types of fertilizers, rock phosphate is not water-soluble and therefore cannot be applied efficiently through fertigation.

Statement 3 is correct: Because fertigation delivers nutrients directly to the root zone of plants, it increases the availability of nutrients to the plants.

Statement 4 is correct: Fertigation allows for the precise application of nutrients, which reduces the risk of nutrient leaching.

Therefore, options 1, 3, and 4 are correct.

Explanation

The Ceylon frogmouth, Coppersmith barbet, Gray-chinned minivet, and White-throated redstart are all species of birds.

The Ceylon frogmouth is a species native to the Western Ghats and parts of Sri Lanka. Known for its unique frog-like appearance and nocturnal habits, it thrives in dense forests.

The Coppersmith barbet is a small, colorful bird found across the Indian subcontinent and parts of Southeast Asia. It is named after the sound it makes, which resembles the sound of a coppersmith striking metal.

The Gray-chinned minivet is a species commonly found in the Indian subcontinent and Southeast Asia. This bird is known for its vibrant plumage and its presence in hilly, forested areas.

The White-throated redstart is a striking bird found in regions of Nepal, Bhutan, central China, and the far northern parts of Myanmar and Northeast India. It is known for its contrasting black and white plumage and bright red tail feathers.

Explanation

Statement 1 is correct: Desert National Park is located in Rajasthan and is one of the largest national parks in India, covering an area of around 3,162 km². It represents the Thar Desert ecosystem, featuring sand dunes, rocky terrain, and sparse vegetation. The park is spread across Jaisalmer and Barmer districts of Rajasthan.

Statement 2 is incorrect: Unlike some protected areas, human settlements exist within Desert National Park. Several villages and communities, including those engaged in livestock rearing, are located inside the park.

Statement 3 is correct: The park is one of the last strongholds of the Great Indian Bustard (Ardeotis nigriceps), which is critically endangered. Conservation efforts, including captive breeding programs, are ongoing to protect this bird. Therefore, the correct answer is that statements 1 and 3 are correct.

Explanation

Statement 1 is correct: Coal ash, a by-product of coal combustion in power plants, contains various heavy metals including arsenic, lead, and mercury. These metals can pose environmental and health hazards. These toxic elements can leach into water bodies and contaminate soil.

Statement 2 is correct: The combustion of coal in power plants releases releases sulfur dioxide (SO₂), which contributes to acid rain and respiratory issues. It also emits oxides of nitrogen (NOₓ), which play a major role in smog formation and air pollution.

Statement 3 is correct: Indian coal, particularly the variety found in the eastern and central regions, is known for its high ash content (30-50%), which reduces its calorific value and increases pollution levels.Due to its high ash content, Indian thermal power plants generate large quantities of fly ash.

Therefore, all three statements are correct.

Explanation

Copper slag is a by-product generated during the extraction and refining of copper. It can be used as a partial replacement for sand in concrete production, thus reducing the demand for natural resources. This reduces the environmental impact associated with sand mining.

Cold mix asphalt technology involves producing asphalt mixtures at lower temperatures compared to traditional hot mix asphalt. This results in reduced energy consumption during production and lower emissions of greenhouse gases. Cold mix asphalt also allows for the use of recycled materials, further enhancing its environmental sustainability.

Geotextiles are synthetic materials used in road construction for various purposes such as soil stabilisation, drainage, and erosion control. They can help in reducing the need for excessive excavation and use of natural resources like stone and gravel, thereby minimizing environmental impact.

Hot mix asphalt technology involves producing asphalt mixtures at high temperatures. While it provides excellent performance properties for roads, it typically requires higher energy consumption during production compared to cold mix asphalt technology.

Portland cement is a key ingredient in concrete production. While it is widely used in construction, its production process is energy-intensive and emits significant amounts of carbon dioxide, contributing to greenhouse gas emissions.

Therefore, the correct answer is A. 1, 2, and 3 only.

Explanation

Statement 1 is incorrect: 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%) as Critical, and 972 units (14%) as Semi-Critical.

Statement 2 is correct: The CGWA was established in 1997 under Section 3(3) of the Environment (Protection) Act, 1986 to regulate and manage groundwater resources.

Statement 3 is correct: India has the largest area under groundwater irrigation in the world. This is due to the country's heavy reliance on agriculture, which is predominantly rain-fed.

Therefore, the correct answer is B. Statements 2 and 3 only.

Explanation

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 inviolate for the purpose of tiger conservation.

Among the options given, Nagarjunsagar-Srisailam Tiger Reserve has the largest area under 'Critical Tiger Habitat'. It spreads over five districts and the total area of the tiger reserve is 3,728 sq. km.

Explanation

Statement 1 is correct: Zero tillage is a method of farming that involves sowing crop seeds directly into the soil without disturbing it. This method has several advantages. In zero tillage, the residue of the previous crop is left on the field, which acts as a natural mulch, reducing soil erosion and improving soil fertility. Therefore, there is no need to burn the residue of the previous crop before sowing wheat.

Statement 2 is correct: In zero tillage, seeds are directly planted into the soil, eliminating the need for a nursery of rice saplings. This not only saves time and labor but also reduces the cost of cultivation.

Statement 3 is correct: Carbon sequestration refers to the process of capture and long-term storage of atmospheric carbon dioxide. In zero tillage, the carbon in the crop residue is returned to the soil, which helps in carbon sequestration.

Therefore, all the three statements are correct.

Explanation

Askot Wildlife Sanctuary (Uttarakhand): Musk deer are found in the high altitudes of the Himalayan region. Askot Wildlife Sanctuary, located in Uttarakhand, is specifically known for conserving the musk deer and its habitat.

Gangotri National Park (Uttarakhand): Gangotri National Park, also located in Uttarakhand, is another high altitude region where musk deer can be found.

Kishanpur Wildlife Sanctuary (Uttar Pradesh): This sanctuary primarily consists of terai grasslands and does not provide a suitable habitat for musk deer.

Manas National Park (Assam): This park is located in the northeastern plains and is home to species like tigers, rhinos, and elephants, but not musk deer.

Therefore, the most likely places to find the musk deer in its natural habitat are Askot Wildlife Sanctuary and Gangotri National Park.

Explanation

Statement 1 is correct: Female elephants, particularly older and more experienced ones, often lead the herd, while males may roam alone or form bachelor groups.

Statement 2 is correct: The gestation period for elephants is indeed one of the longest among mammals, ranging from about 18 to 22 months.

Statement 3 is incorrect: Female elephants can continue to reproduce well into their 40s and sometimes even into their 50s, although their reproductive capability tends to decrease with age.

Statement 4 is incorrect: Kerala does have a significant elephant population, but the highest elephant population in India is typically found in the state of Karnataka, followed by Assam.

Explanation

The question is asking about the raw materials that can be used for the production of biofuels according to India�s National Policy on Biofuels.

Cassava is a starch-rich root vegetable that can be used to produce biofuel.

Damaged wheat grains, which are unfit for human consumption, can also be used to produce biofuel.

Groundnut seeds are not mentioned in the National Policy on Biofuels as a raw material for biofuel production.

Horse gram is also not mentioned in the National Policy on Biofuels as a raw material for biofuel production.

Rotten potatoes, which are unfit for human consumption, can be used to produce biofuel.

Sugar beet is a plant whose root contains a high concentration of sucrose and it is grown commercially for sugar production. It can also be used to produce biofuel.

Therefore, according to India�s National Policy on Biofuels, Cassava, Damaged wheat grains, Rotten potatoes, and Sugar beet can be used as raw materials for the production of biofuels.

Explanation

Solar pumps provide a clean, energy-efficient, and sustainable alternative to traditional electric and fuel-driven pump sets. They play a crucial role in environmentally friendly agriculture and can be implemented in both developed and underdeveloped regions. The main components in a solar pumping system include a photovoltaic (PV) array, an electric motor and a pump. Solar water pumping systems are classified as either direct current (DC) or alternating current (AC) systems based on the motors ability. Recently, the concept of brushless DC (BLDC) motors for solar pumping water applications was presented as well.

Statement 1 is incorrect: Solar power can be used to run both surface pumps and submersible pumps. The type of pump does not limit the use of solar power.

Statement 2 is incorrect: Solar power can be used to run both centrifugal pumps and piston pumps. The type of pump, whether it's a centrifugal pump or a piston pump, does not limit the use of solar power.

Hence, both statements 1 and 2 are incorrect.

Explanation

The Wildlife Protection Act, 1972, provides for the protection of wild animals, birds, and plants. It classifies species into six schedules, each offering different levels of protection.

Schedule VI of the Act pertains to certain plants that are prohibited from cultivation and planting without a license. Therefore, If a plant species is listed under Schedule VI, it means a license is required for its cultivation.

The Wild Life (Protection) Amendment Act, 2022 amended the Wild Life (Protection) Act, 1972. The amendment reduced the number of schedules from six to four, simplifying wildlife classification and protection levels. Additionally, the Act also aligned the provisions with CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) by introducing a separate schedule (Sch. IV) for species covered under CITES.