Environment and Ecology: UPSC Previous Year Questions (Prelims)

Explanation

Statement 1 is incorrect: Indian squirrels, such as the Indian Palm Squirrel, do not burrow in the ground to build nests. Instead, they construct nests in trees, crevices, or other elevated areas using materials like leaves and twigs. Burrow-making is more characteristic of rodents like rats or ground squirrels, which are not typical Indian squirrels.

Statement 2 is correct: Nuts serve as the primary food source for these creatures year-round, especially during the winter months when they are preparing for hibernation. They store nuts by burying them underground, enabling retrieval during the win-ter season.

Statement 3 is correct: Squirrels are omnivores. Their diet primarily consists of nuts and fruits, although they will also consume seeds, insects, small mammals, reptiles, eggs, and occasionally even bird chicks.

Explanation

Statement-I is correct: Although India has significant uranium deposits, its reliance on coal for electricity production is higher compared to uranium. It constitutes 55% of the nation’s energy requirements. Statement-II is incorrect: For electricity generation, uranium enrichment to a level of 3 to 5 percent of the Uranium (235) isotope is necessary. Research reactors utilise uranium enriched to a minimum concentration of 20%. Uranium enriched to at least 90% is classified as weapons-grade uranium.

Explanation

The UNOPS Sustainable Investments in Infrastructure and Innovation (S3i) initiative was introduced in 2015 as a pilot project to investigate inventive approaches to financing sustainable infrastructure endeavours in developing nations. The initiative sought to capitalise on UNOPS’ proficiency and track record in providing infrastructure solutions that align with the requirements and ambitions of individuals and communities. The S3i initiative provides initial funding for significant projects in affordable housing, renewable energy, and health infrastructure. It does not emphasise investments in mass rapid transport infrastructure.

Explanation

Alfalfa, chickpea, and clover are nitrogen-fixing plants. They belong to the leguminous family and form symbiotic associations with Rhizobium bacteria in their root nodules, aiding in nitrogen fixation and enriching soil fertility. Amaranth, purslane (Kulfa), and spinach, are non-legumi-nous plants and lack the ability to fix nitrogen as they do not form symbiotic relationships with nitrogen-fixing bacteria or develop root nodules. This natural ability of legumes like alfalfa, chickpea, and clover to fix nitrogen is extensively utilized in crop rotation practices to replenish soil nutrients and enhance agricultural productivity.

Explanation

Methane (CH₄) and nitrous oxide (N₂O) are the two most important GHGs after carbon dioxide (CO₂). The most rapid increase in CH₄ emission was found in natural wetlands and rice fields due to increased rice cultivation area and climate warming. N₂O emission increased substantially in all the biome types and the largest increase occurred in upland crops due to increasing air temperature and nitrogen fertilizer use. Rice paddies are considered one of the most important sources of CH₄ and N₂O emissions, which have attracted considerable attention due to their contribution to global warming.

Explanation

The System of Rice Intensification involves cultivating rice with as much organic manure as possible, starting with young seedlings planted singly at wider spacing in a square pattern; and with intermittent irrigation that keeps the soil moist but not inundated, and frequent inter cultivation with weeder that actively aerates the soil. SRI is not a standardised, fixed technological method. It is rather a set of ideas, a methodology for comprehensively managing and conserving resources by changing the way that land, seeds, water, nutrients, and human labour are used to increase productivity from a small but well-tended number of seeds. Advantages of SRI Disadvantages of SRI Higher yields - Both grain and straw Higher labour costs in the initial years Reduced duration Difficulties in acquiring the necessary skills Reduced seed requirement Not suitable when no irrigation source available Lesser chemical inputs Less water requirement Reduced electricity consumption Less chaffy grain rain weight increased without change in grain size Higher head rice recovery Withstand cyclonic gales Cold tolerance Soil health improves through biological activity Reduced methane production

Explanation

The updated (2021) WHO Global Air Quality Guidelines (AQGs) provide recommendations on air quality guideline levels as well as interim targets for six key air pollutants. The guidelines focus on so-called classical pollutants, particulate matter (PM. and PM), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and carbon monoxide (CO).

Statement 1 is correct: The 24-hour ceiling mean of PM 2.5 used to be 25 micrograms but has now dropped to 15.

Statement 2 is incorrect: Ozone at ground level is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NOx) from vehicle and industry emissions and volatile organic compounds (VOCs) emitted by vehicles, solvents and industry. As a result, the highest levels of ozone pollution occur during periods of sunny weather and not during inclement weather.

Statement 3 is incorrect: Particles with a diameter of 10 m (PM10) can reach the lungs but cannot enter the bloodstream. However, particles with a diameter of 2.5 m or less can penetrate deeper into the lungs, reaching the alveoli, enter the bloodstream, and potentially cross blood-organ barriers, impacting various organs such as the brain, heart, liver, and kidneys. PM (10 microns) can reach deep into the lungs, but the more harmful PM. (2.5 microns) can penetrate the lung barrier and enter the bloodstream, posing severe health risks.

Statement 4 is correct: Excessive ozone in the air can have a marked effect on human health. It causes breathing problems, triggers asthma, reduces lung function and causes lung diseases. Ozone triggers asthma because it is very irritating to the lungs and airways.

Explanation

Normal rain has a pH of about 5.6 when pH falls below this; it is called Acid rain (pH 4.2 to 4.4). Acid rain results when Sulfur Dioxide (SO₂) & Nitrogen Oxides (NOX) react with water, oxygen & other chemicals to form Sulfuric & Nitric acids. Nitrous oxide and Sulphur dioxide cause Acid rain. The acid rain harms microorganisms in the soil; inhibits the activity of nitrogen fixation bacteria; soil acidification; ocean acidification; affects the growth of plants; food chain; kills aquatic animals; corrosion of metals & weathering of stone buildings & statues. NOx + SO₂ + Moisture + other chemicals Acid Rain (HNO₃ + H₂ SO₄)

Explanation

Statement 1 is correct: The Climate Group is an inter-national non-profit organization that works to accelerate climate action by building and running large networks of businesses, governments, and other organizations. It focuses on initiatives like RE100 (renewable energy), EP100 (energy productivity), and EV100 (electric vehicles).

Statement 2 is incorrect: The EP100 initiative is led by the Climate Group in partnership with the Alliance to Save Energy, not the International Energy Agency (IEA).

Statement 3 is correct: EP100 is a global initiative that encourages companies to commit to doubling their energy productivity (output per unit of energy consumed). This helps drive innovation, increase competitiveness, and reduce greenhouse gas emissions.

Statement 4 is correct: Several Indian companies, such as Mahindra & Mahindra, Godrej and Dalmia Cement, are members of EP100 and have committed to improving their energy productivity.

Statement 5 is incorrect: EP100 is a global initiative that brings together companies committed to improving energy productivity. The Under2 Coalition is a global alliance of state and regional governments committed to reducing greenhouse gas emissions. Its Secretariat is managed by Climate Group.

Explanation

Option (a) is correct: The Climate Action Tracker (CAT) is an independent scientific project that monitors government climate action and measures it against the globally agreed Paris Agreement aim of "holding warming well below 2°C, and pursuing efforts to limit warming to 1.5°C." It is a collaboration between Climate Analytics and the New Climate Institute. CAT has been providing assessments since 2009. It evaluates countries’ emission reduction pledges, policies, and their impact on global warming. Options (b), (c) and (d) are incorrect:

The Climate Action Tracker is neither a part of the Intergovernmental Panel on Climate Change (IPCC) nor the UNFCCC. The IPCC is a separate body that assesses scientific, technical, and socio-economic information related to climate change. The UNFCCC is an international treaty that provides the framework for global climate negotiations. The Climate Action Tracker is not funded or promoted by the United Nations Environment Programme (UNEP) or the World Bank. It is an independent initiative run by research organizations.