Environment

Direct Air Capture (DAC) is a technology that removes CO₂ directly from the air for storage or use in various industries.

Statement I is correct: * DAC captures CO₂ for carbon sequestration, reducing greenhouse gases.

Statement II is correct: * Captured CO₂ can be used to make plastics and in food processing.

Statement III is correct: * DAC provides carbon to make synthetic low-carbon aviation fuels by combining with hydrogen.

So, the correct answer is: C

Pair I – Cassava: Woody shrub → Correct Cassava (also called tapioca or manioc) is indeed a woody shrub cultivated for its starchy tuberous roots.

Pair II – Ginger: Herb with pseudostem → Correct Ginger is a herbaceous perennial with a pseudostem formed by leaf sheaths; the edible part is the rhizome.

Pair III – Malabar spinach: Herbaceous climber → Correct Malabar spinach (Basella alba) is a soft, herbaceous twining climber, commonly grown as a leafy vegetable.

Pair IV – Mint: Annual shrub → Incorrect Mint (Mentha spp.) is not a shrub; it is a perennial herb with soft stems, spreading by stolons.

Pair V – Papaya: Woody shrub → Incorrect Papaya (Carica papaya) is a herbaceous tree (giant herb), not a woody shrub—it has a soft, hollow stem.

Cement manufacturing contributes significantly to global carbon emissions, mainly due to the chemical process involved in producing clinker.

Statement I: Cement industry emissions are estimated to be around 5-8% of global CO₂ emissions, making it a major source of greenhouse gases. Statement II: Silica-bearing clay is indeed mixed with limestone during cement making to provide essential minerals like silicon, aluminum, and iron needed for the final product. Statement III: During clinker production, limestone (calcium carbonate) is heated and converted into lime (calcium oxide), releasing CO₂ in the process. This calcination is the main source of carbon emissions in cement manufacturing.

Both Statements II and III are correct, but only Statement III directly explains the source of carbon emissions mentioned in Statement I.

A circular economy focuses on minimizing waste, reusing resources, and improving efficiency, all of which help lower greenhouse gas emissions and conserve raw materials.

Statement I: Correct By reducing waste and energy use, the circular economy helps cut greenhouse gas emissions.

Statement II: Correct It reduces the need for raw materials through reuse, recycling, and product life extension.

Statement III: Correct It also lowers production waste using efficient and sustainable design and processes.

Many everyday items contain hidden plastics, even if they don't look like typical plastic products.

* I. Cigarette butts – Filters are made of cellulose acetate, a form of plastic. * II. Eyeglass lenses – Usually made from polycarbonate or CR-39 plastic, not glass. * III. Car tyres – Contain synthetic rubber, which includes plastic-based polymers.

All three items contain plastic.

Statement I is correct: The World Bank's report on India's cooling sector and climate vulnerability highlights that extreme heat stress (wet-bulb temperatures) is linked to a wider set of climate implications, including more frequent and intense tropical cyclones, flooding, and droughts, particularly affecting the vulnerable Peninsular region.

Statement II is correct: The wet-bulb temperature is a measure that combines heat and humidity. At 35°C wet-bulb, the air is too saturated for sweat to evaporate, preventing the body from shedding heat. This makes survival physically impossible for humans and animals without external cooling.

A. The European Union: The Nature Restoration Law (NRL) is an EU legislative initiative adopted in 2024. It sets binding targets to restore ecosystems, fight climate change, and protect biodiversity across EU member states.

B. The World Bank: An international financial institution providing loans and grants; it does not enact laws like the NRL.

C. OECD: An organization promoting economic cooperation and policy coordination; it does not enact binding environmental laws such as the NRL.

D. FAO: A UN agency focused on hunger and agriculture; it does not enact regional laws like the NRL.

India's CO₂ emissions come mainly from fuel combustion, especially electricity generation, and per capita emissions are higher than 0.5 tonnes.

Statement I is incorrect: * India's per capita CO₂ emissions are around 1.9-2.0 tonnes, higher than 0.5 t CO₂/capita.

Statement II is correct: * India ranks second in the Asia-Pacific for total CO₂ emissions from fuel combustion, after China.

Statement III is correct: * Electricity and heat production (mainly coal-based) is the largest source of India's CO₂ emissions.

So, the correct answer is: C

Activated carbon is widely used to clean pollutants because of its unique properties and sustainable production methods.

Statement I: Correct. Activated carbon effectively removes pollutants from industrial effluents due to its high adsorption capacity. It's commonly used in water treatment and pollution control. Statement II: Correct. This is because activated carbon has an extremely large surface area, created by its porous structure, allowing it to trap heavy metals and other contaminants efficiently. Statement III: Correct. Moreover, activated carbon can be produced easily and cost-effectively from carbon-rich wastes like coconut shells, rice husks, and other agricultural residues, making it an eco-friendly option.

Thus, both Statement II and Statement III are correct, and together they explain why Statement I is true.

A. silver iodide and potassium iodide: True Both are used in cloud seeding because their crystalline structures help form ice nuclei, inducing rainfall.

B. silver nitrate and potassium iodide: False Silver nitrate is not used for artificial rainmaking.

C. silver iodide and potassium nitrate: False Potassium nitrate is not used in cloud seeding.

D. silver nitrate and potassium chloride: False Neither chemical is used in artificial rainmaking.

Therefore, option A is correct.

Nature-based solutions involve using natural processes to tackle climate change and biodiversity loss, often needing dedicated financial support.

ADB launched the Nature Solutions Finance Hub for Asia and the Pacific to fund nature-based solutions for climate and environmental challenges in the region.

The Peacock tarantula (Gooty tarantula) is a rare, tree-dwelling spider found in limited forest areas in India.

Statement I is incorrect: * It is a spider (arachnid), not an omnivorous crustacean.

Statement II is correct: * Its habitat is restricted to some forest areas in the Eastern Ghats.

Statement III is correct: * It is arboreal, living in trees and tree crevices.

So, the correct answer is: D

At COP28, India chose not to sign the "Declaration on Climate and Health," and this decision can be understood by analyzing the nature of the declaration and India's concerns.

Statement I: Correct. India did not sign the COP28 Declaration on Climate and Health, unlike over 120 other countries.

Statement II: Incorrect. The declaration is not legally binding; it is a voluntary political commitment. Signing it does not legally mandate countries to decarbonize their health sectors immediately.

Statement III: Correct. India's concern is that rapid decarbonization of its health sector could compromise the resilience and accessibility of healthcare services, given current developmental challenges and resource constraints.

Therefore, only Statement III correctly explains Statement I, while Statement II is factually wrong about the binding nature of the declaration.

Article 6 of the Paris Agreement is crucial as it outlines international cooperation through both carbon markets and non-market approaches to help countries meet climate goals.

Statement I is correct: * Article 6 is widely discussed because it enables cooperation through market and non-market means to fight climate change.

Statement II is correct: * It defines rules for carbon markets, including carbon trading and credit mechanisms.

Statement III is correct: * It also promotes non-market tools like technology transfer and capacity building to reach climate targets.

So, the correct answer is: A

Oxygen on Earth mainly comes from photosynthesis, especially by phytoplankton (marine organisms), and oxygen levels differ between air and water.

Statement I is incorrect: * Oceans (phytoplankton) produce more oxygen than rainforests.

Statement II is correct: * Marine phytoplankton and photosynthetic bacteria produce about 50% of the world's oxygen.

Statement III is incorrect: * Atmospheric air has much more oxygen than surface water; water does not contain several folds higher oxygen than air.

So, the correct answer is: B

* Agricultural residues: These include materials like crop stalks, husks, and leaves. They are a viable source of biomass that can be converted into biofuels, including Sustainable Aviation Fuel (SAF).

* Corn grain: Corn grain is a source of sugars that can be fermented to produce ethanol, a biofuel. While ethanol is primarily used in gasoline blends, it can also be further processed into SAF.

* Wastewater treatment sludge: This sludge is rich in organic matter. Through processes like anaerobic digestion, it can produce biogas, which can be further converted into SAF.

* Wood mill waste: This includes sawdust, wood chips, and bark. These lignocellulosic materials can be converted into biofuels through various thermochemical or biochemical processes, ultimately leading to SAF production.


Therefore, all four materials can be used as feedstock for producing Sustainable Aviation Fuel.

* Cicada: Known for their loud buzzing sounds, cicadas are insects.

* Froghopper: Also known as spittlebugs, they are small, jumping insects.

* Pond Skater: These insects are known for their ability to walk on the surface of water.

All three organisms are classified as insects.

Fig-Wasp Mutualism: Figs and fig wasps share an obligate mutualistic relationship, meaning they are entirely dependent on each other for survival and reproduction. Fig wasps are the only insects that can pollinate fig trees, and fig trees are the sole source of food and shelter for developing fig wasps.

Highly Specialized Pollination: The fig fruit (technically a syconium) has its flowers enclosed within. Female fig wasps enter the syconium through a tiny opening called the ostiole. They lay eggs inside and pollinate the flowers in the process.


Coevolution: This intricate relationship is a classic example of coevolution, where two species have evolved together over millions of years, with each species' adaptations influencing the other's.

_The other options are incorrect:_

* Mahua (B): It is pollinated by various insects and even bats. Mahua (Madhuca indica) is found in the dry deciduous type of forests like the Forests of Chhattisgarh and Jharkhand.

* Sandalwood (C): It is primarily pollinated by bees and flies. Sandalwood is a dry deciduous forest species native to China, India, Indonesia, Australia, and the Philippines. Sandalwood is listed as Vulnerable in the IUCN Red list. Sandalwood grows as a partial or hemiparasite, relying on the presence of four or five other trees nearby. Beneath the ground, its roots develop a haustorium, an octopus-like structure that attaches to the host tree's roots, drawing water and nutrients from them.

* Silk cotton (D): It is pollinated by bats and birds. The Silk Cotton Tree is a tropical deciduous tree native to the Indian subcontinent and other parts of Southeast Asia. It produces a capsule that, when ripe, contains white fibres like cotton.

Statement-I: Correct.

Chewing gums are a source of environmental pollution due to several factors:

* Non-biodegradable gum base: Traditional chewing gums often contain polymers like polyisobutylene, polyvinyl acetate, or polyethylene, which do not decompose easily in the environment.

* Littering: Discarded chewing gum remains on sidewalks, streets, and other public spaces, creating an eyesore and requiring significant resources for removal.

Statement-II: Correct and explains Statement-I

* The plastic-like polymers used as gum bases in many chewing gums are the primary reason they are difficult to biodegrade. These polymers contribute significantly to the environmental persistence of chewing gum litter.

Therefore, the correct option is (A): Both Statement-I and Statement-II are correct and Statement-II explains Statement-I.

The Congo Basin is home to the Cuvette Centrale, which is the world's largest tropical peatland complex. Spanning the Republic of Congo and the Democratic Republic of Congo, this peatland covers about 145,000 square kilometres and stores approximately 30 billion tonnes of carbon—a value roughly equivalent to three years of global fossil fuel emissions. The protection of this region is highlighted by the Brazzaville Declaration (2018), signed by the Republic of Congo, the Democratic Republic of Congo, and Indonesia, to prevent land-use changes and drainage that would release this stored carbon and exacerbate global climate change.

* Statement 1 is Correct. PFAS are used in a wide range of consumer products, and due to their persistence, they can leach into the environment and contaminate water sources, food, and packaging materials.

* Statement 2 is Correct. PFAS are known as 'forever chemicals' because the strong carbon-fluorine bond makes them highly resistant to natural degradation processes. This persistence leads to their accumulation in the environment.

* Statement 3 is Correct. Because PFAS don't break down easily, they can build up in the tissues of animals and humans over time, leading to potential health concerns.


_Therefore, all three statements are correct._

1. Carabid beetles: Many carabid beetles are predatory, and some species are known to be parasitoids, particularly of other insects.

2. Centipedes: Centipedes are predatory arthropods and not parasitoids. They hunt and kill their prey.

3. Flies: The order Diptera (flies) includes a large number of parasitoid species. For example, Tachinid flies are parasitoids of various insects.

4. Termites: Termites are not parasitoids. They are social insects that primarily feed on wood and other plant matter.

5. Wasps: The order Hymenoptera (wasps, bees, ants) has numerous parasitoid species. Many wasp species are parasitoids, laying their eggs on or in other insects.

_Therefore, parasitoid species are found in Carabid beetles, Flies, and Wasps._

Power plants burning fossil fuels (coal, oil, and, to a lesser extent, natural gas) are the largest source of sulfur dioxide emissions globally. Coal, in particular, contains high levels of sulfur, and when burned, it releases large amounts of SO₂.

* Locomotives, especially older ones, use diesel fuel which contains sulfur. While locomotives do contribute to sulfur dioxide (SO₂) emissions, their contribution is relatively minor compared to larger industrial sources.

* Ships, particularly large cargo vessels and tankers, often use bunker fuel, a heavy, sulfur-rich fuel oil. This contributes significantly to SO₂ emissions, particularly in maritime regions. However, they are still overshadowed by emissions from power plants

* The process of extraction of metals from ore involves heating ores that contain sulfur compounds, releasing SO₂ into the atmosphere. However, its contribution is less than that of power plants.

* Membrane Bioreactors are often discussed in the context of: D. Wastewater treatment technologies.

* Membrane Bioreactors (MBRs) combine a membrane process like microfiltration or ultrafiltration with a biological wastewater treatment process. * They are used to improve the quality of treated wastewater and are known for their efficiency in removing contaminants.

* Statement 1 is correct. Lions can breed throughout the year, but they do show some seasonal preferences depending on their location and environmental factors like rainfall.

* Statement 2 is correct. Cheetahs have a different vocal structure compared to lions, tigers, leopards, and jaguars, preventing them from roaring. They purr, chirp, and make other bird-like sounds.

* Statement 3 is incorrect. Both male lions and male leopards use scent marking extensively to define their territories. They spray urine and scrape the ground, leaving both olfactory and visual signals for other cats.

_Therefore, only statements 1 and 2 are correct._

Statement 1 is incorrect. Insolation reaches the earth's surface in short waves and heat is radiated from the earth in long waves, Hence energy leaving the earth's surface i.e. terrestrial radiation heats up the atmosphere more than the incoming solar radiation i.e. insolation.


Statement 2 is correct. Greenhouse gases in the atmosphere (such as water vapour and carbon dioxide) absorb most of the Earth's emitted longwave infrared radiation, which heats the lower atmosphere.

* Butterflies: Some butterfly species, like the Monarch butterfly, are poisonous. They consume milkweed during their larval stage, which makes them toxic to predators.

* Fish: Many fish species are poisonous, such as pufferfish, lionfish, and stonefish. They possess venom as a defense mechanism.

* Frogs: Poison dart frogs are a well-known example of poisonous frogs. Their skin secretes toxins that can be deadly.

_Therefore, all three groups have poisonous species._

Statement-I is incorrect: Following the Wild Life (Protection) Amendment Act, 2022, the number of schedules was reduced from six to four. Schedule V (the vermin category) was abolished. The Indian Flying Fox is currently listed under Schedule II, providing it with higher protection. It is no longer legally classified as "vermin" under the Act.

Statement-II is incorrect: The Indian Flying Fox is one of the largest bats in the world and is a frugivore. Its diet consists of fruits (like mangoes, guavas, and figs) and nectar. It does not feed on blood; "vampire bats" are a different group of species found primarily in Central and South America.

Note: None of the option is correct as both options are incorrect, UPSC dropped this question from the final answer key.

* Statement 1 is Correct: Gold mining is poisoning Amazon forests with mercury. To separate the gold, miners mix liquid mercury into the sediment, which forms a coating around the gold.

* Statement 2 is Correct: Fly ash generated by TPPs is one of the ways mercury is released into the environment. Fly ash is usually disposed of in ash ponds in the form of ash slurry, forming an aquatic ecosystem of its own. Coal-based TPPs are the major source of mercury – the ninth most toxic element found on earth — emissions into the environment. Mercury contributed over 80 percent of emissions released by the TPPs, according to 2016 estimates by the Delhi-based think-tank Centre for Science and Environment.

* Statement 3 is Incorrect: While mercury is unquestionably toxic, toxicology works on the principle of dose: "The dose makes the poison." Hence, scientific bodies define reference doses (RfD) or tolerable intake levels, not zero exposure. WHO's Provisional Tolerable Weekly Intake (PTWI) for methylmercury (from fish) → 1.6 µg/kg body weight/week and 1 µg/litre for total mercury in drinking water. If no safe level truly existed: Mercury would be completely banned, not regulated.

NOTE: UPSC usually considers extreme statement to be wrong.

* Green hydrogen is the hydrogen produced through electrolysis of water using electricity from renewable sources.

* Green hydrogen is expected to play a significant role in decarbonizing all three of the mentioned heavy industries.

* Green hydrogen can be used in the production of ammonia, which is a key component for many fertilizers. Fertilizer production is energy-intensive and often relies on fossil fuels, particularly natural gas. By using green hydrogen as a clean energy source, the carbon emissions from this industry can be significantly reduced

* Green hydrogen can be used in oil refineries to process crude oil into various products, including gasoline, diesel, and jet fuel. This can help to reduce the carbon emissions from the refining process.

* The steel industry is one of the largest industrial emitters of carbon dioxide. Green hydrogen can be used in place of coal in the steelmaking process, significantly reducing the industry's carbon emissions.