UPSC Prelims 2025 Analysis

Explanation

Statement I: Incorrect While rainforests are vital ecosystems, oceans are the primary producers of oxygen on Earth. Marine phytoplankton, through photosynthesis, contribute a significantly larger portion of the world's oxygen compared to rainforests.

Statement II: Correct Marine phytoplankton, including algae and photosynthetic bacteria like cyanobacteria, are responsible for a significant portion of global oxygen production. Scientific estimates suggest they produce about 50% of the world's oxygen. This is due to their vast numbers and widespread distribution in the oceans.

Statement III: Incorrect Atmospheric air contains significantly more oxygen than well-oxygenated surface water. Air is composed of roughly 21% oxygen, while the amount of dissolved oxygen in water is much lower, typically measured in parts per million (ppm). Therefore, water does not contain 'several folds higher oxygen' than atmospheric air.

Therefore, only statement II is correct.

Explanation

Statement I Analysis: Article 6 of the Paris Agreement is indeed frequently discussed in global climate discussions. It deals with international cooperation mechanisms for achieving climate targets, making it a central topic in sustainable development and climate change negotiations. This statement is TRUE.

Statement II Analysis: Article 6 of the Paris Agreement does establish principles for carbon markets. Specifically:

• Article 6.2 covers internationally transferred mitigation outcomes (ITMOs) - essentially international carbon trading
• Article 6.4 establishes a centralized crediting mechanism (successor to CDM)
• Article 6.8 addresses non-market approaches

The article sets out key principles like avoiding double counting, ensuring environmental integrity, and promoting sustainable development. This statement is TRUE.

Statement III Analysis: Article 6 does include provisions for non-market approaches. Article 6.8 specifically recognizes 'non-market approaches' as a mechanism for international cooperation. These include:

• Technology transfer
• Capacity building
• Climate finance
• Policy coordination

These non-market strategies are designed to help countries achieve their Nationally Determined Contributions (NDCs). This statement is TRUE.

Relationship Analysis: Both Statement II and III correctly explain why Statement I is true. Article 6 is frequently discussed precisely because it covers both market mechanisms (carbon markets) and non-market approaches for international climate cooperation. Both aspects make it a crucial component of global climate discussions.

Conclusion: All three statements are correct, and both Statement II and Statement III explain Statement I by describing the key components of Article 6 that make it so frequently discussed in climate negotiations.

Explanation

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.

Explanation

Statement I: Incorrect The Peacock tarantula (Gooty tarantula), scientifically known as 'Poecilotheria metallica', is not a crustacean. It is an arachnid (a spider), not related to crustaceans like crabs or lobsters. Additionally, it is primarily insectivorous, feeding on insects and other small animals, not omnivorous.

Statement II: Correct The natural habitat of the Gooty tarantula in India is extremely limited. It is found only in a few forested areas, particularly in the Eastern Ghats of Andhra Pradesh. Its distribution is highly restricted and fragmented.

Statement III: Correct In its natural habitat, the Gooty tarantula is an arboreal species, meaning it lives in trees. It constructs silken retreats in tree holes and crevices.

Therefore, statements II and III are correct.

Explanation

The correct answer is (A) The Asian Development Bank (ADB)

Here's why:

• A. The Asian Development Bank (ADB): The Asian Development Bank (ADB) launched the 'Nature Solutions Finance Hub for Asia and the Pacific'. This initiative aims to mobilize finance for nature-based solutions to address climate change, biodiversity loss, and other environmental challenges in the Asia-Pacific region.
• B. The Asian Infrastructure Investment Bank (AIIB): While AIIB also invests in sustainable infrastructure, it did not launch the 'Nature Solutions Finance Hub for Asia and the Pacific'.
• C. The New Development Bank (NDB): NDB focuses on infrastructure and sustainable development projects in BRICS countries and other emerging economies. It did not launch the mentioned hub.
• D. The International Bank for Reconstruction and Development (IBRD): IBRD, part of the World Bank Group, operates globally and supports development projects. However, it was not the institution that launched the 'Nature Solutions Finance Hub for Asia and the Pacific'.

Therefore, option A is the most accurate answer as it directly identifies the organization responsible for launching the 'Nature Solutions Finance Hub for Asia and the Pacific'.

Explanation

• A. silver iodide and potassium iodide: TRUE. Artificial rainmaking, also known as cloud seeding, commonly uses silver iodide (AgI) and sometimes potassium iodide (KI) as seeding agents. These substances have a crystalline structure similar to ice, which helps in the formation of ice nuclei in clouds, leading to precipitation (rainfall). Silver iodide is the most widely used chemical for this purpose globally.

• B. silver nitrate and potassium iodide: FALSE. Silver nitrate (AgNO3) is not used in cloud seeding. While potassium iodide can be used, silver nitrate is not effective for inducing rainfall.

• C. silver iodide and potassium nitrate: FALSE. Potassium nitrate (KNO3) is not used in cloud seeding. Silver iodide is correct, but potassium nitrate is not.

• D. silver nitrate and potassium chloride: FALSE. Neither silver nitrate nor potassium chloride are used for artificial rainmaking.

Therefore, option A is correct as both silver iodide and potassium iodide are used in artificial rainmaking to induce rainfall and reduce air pollution.

Explanation

Statement I: Correct Activated carbon is indeed a widely used and effective tool for removing pollutants from wastewater and industrial effluents. Its effectiveness stems from its ability to adsorb a variety of contaminants.

Statement II: Correct Activated carbon has a very high surface area due to its porous structure, which makes it an excellent adsorbent. It also possesses a significant capacity for adsorbing heavy metals from solutions.

Statement III: Correct Activated carbon can be synthesized from a variety of carbon-rich waste materials, including agricultural waste (e.g., coconut shells, rice husks), industrial by-products, and even certain types of plastic waste. This makes its production more sustainable and cost-effective.

Both Statement II and Statement III explain Statement I, because the properties of large surface area and strong potential for adsorbing heavy metals (Statement II), and the possibility of easy synthesis from environmental wastes with high carbon content (Statement III) contribute to activated carbon being a good tool to remove pollutants.

Therefore, both Statement II and Statement III are correct and both of them explain Statement I.

Explanation

Statement I: Incorrect India's per capita CO₂ emissions are actually higher than 0.5 t CO₂/capita. According to recent data from the Global Carbon Atlas and IEA, India's per capita CO₂ emissions are approximately 1.9-2.0 tonnes per capita as of 2020-2022. While this is still significantly lower than developed countries like the USA (15-16 t CO₂/capita) or China (7-8 t CO₂/capita), it exceeds the 0.5 threshold mentioned in the statement.

Statement II: Correct India indeed ranks second in the Asia-Pacific region in terms of absolute CO₂ emissions from fuel combustion, after China. China is the largest emitter globally and in Asia-Pacific, followed by India. Other major emitters in the region like Japan, South Korea, and Australia have much smaller absolute emissions compared to India, though some may have higher per capita emissions.

Statement III: Correct Electricity and heat production sector is indeed the largest source of CO₂ emissions in India, accounting for approximately 44-48% of total CO₂ emissions. This is primarily due to India's heavy reliance on coal-fired power plants for electricity generation. Coal accounts for about 70% of India's electricity generation, making the power sector the dominant contributor to CO₂ emissions. Other sectors like industry, transportation, and residential follow but contribute lesser percentages.

Therefore, statements II and III are correct.

Explanation

• A. The European Union: The Nature Restoration Law (NRL) is a legislative initiative of the European Union. It was proposed by the European Commission and adopted by the European Parliament and Council in 2024. The law aims to restore degraded ecosystems, tackle climate change, and halt biodiversity loss across EU member states. It sets legally binding targets for nature restoration on land and sea within the EU.

• B. The World Bank: The World Bank is an international financial institution that provides loans and grants to countries for development projects. It does not enact laws like the NRL; rather, it supports projects and policies globally.

• C. The Organization for Economic Cooperation and Development (OECD): The OECD is an international organization that promotes economic growth and policy coordination among member countries. It does not have the authority to enact binding environmental laws like the NRL.

• D. The Food and Agriculture Organization (FAO): The FAO is a specialized agency of the United Nations focused on defeating hunger and improving agriculture. It does not enact regional laws such as the NRL.

Explanation

Statement I: Incorrect The statement talks about Peninsular India suffering from flooding, tropical cyclones, and droughts. While these are indeed climate risks for Peninsular India, the specific warning from the World Bank about 'wet-bulb temperatures routinely exceeding 35°C' is not directly about these hazards. Wet-bulb temperature is a measure of heat and humidity, and when it exceeds 35°C, it becomes physiologically dangerous for humans and animals. The World Bank's warning is about the risk to human and animal survival due to extreme heat and humidity, not specifically about flooding, cyclones, or droughts.

Statement II: Correct This statement correctly reflects the implication of the report. Wet-bulb temperatures above 35°C mean that the human body cannot cool itself by sweating, leading to a high risk of heat stress and even death. This affects the survival of both humans and animals, as their ability to shed body heat through perspiration or other means becomes ineffective.

Therefore, only Statement II is correct.

Explanation

I. Cigarette butts: Correct Cigarette butts contain a filter made of cellulose acetate, which is a type of plastic. They are a major source of microplastic pollution.

II. Eyeglass lenses: Correct Most modern eyeglass lenses are made from polycarbonate or CR-39 plastic, not glass. Thus, they contain plastic.

III. Car tyres: Correct Car tyres are made from a blend of natural rubber and synthetic polymers (such as styrene-butadiene rubber), which are types of plastic. Tyres also contain other materials, but plastics are a significant component.

Therefore, all three items contain plastic.

Explanation

Statement I: Circular economy reduces the emissions of greenhouse gases. Correct. A circular economy aims to minimize waste and pollution, keep products and materials in use, and regenerate natural systems. By reducing reliance on virgin raw materials and promoting reuse, repair, and recycling, it significantly lowers greenhouse gas emissions associated with resource extraction, manufacturing, and waste disposal.

Statement II: Circular economy reduces the use of raw materials as inputs. Correct. A core principle of the circular economy is to minimize the need for new raw materials. This is achieved through strategies like product lifespan extension, reuse, repair, refurbishment, and recycling. By keeping materials in use for longer, the demand for virgin resources is reduced.

Statement III: Circular economy reduces wastage in the production process. Correct. The circular economy emphasizes efficient resource utilization and waste minimization at every stage of the production process. This involves strategies such as eco-design, closed-loop manufacturing, and industrial symbiosis, all aimed at reducing waste generation.

Relationship between Statements: Statement II and Statement III both directly contribute to Statement I. Reduced raw material use (Statement II) translates to less energy consumed in extraction and processing, leading to lower greenhouse gas emissions. Similarly, reduced wastage (Statement III) means less material ending up in landfills or incinerators, which are significant sources of greenhouse gas emissions. Thus, both statements help explain why a circular economy reduces greenhouse gas emissions.

Therefore, Statement II and III are correct and both of them explain statement I.

Explanation

The correct answer is (B) Both Statement II and Statement III are correct but only one of them explains Statement I

Here's why:

• Statement I: Studies indeed suggest that the cement industry is a significant contributor to global carbon emissions. The percentage is generally estimated to be around 5-8%. This statement is correct.

• Statement II: In cement manufacturing, raw materials like silica-bearing clay and limestone are mixed. This provides the necessary elements (calcium, silicon, aluminum, and iron) for the cement compounds. This statement is correct.

• Statement III: During the clinker production stage, limestone (calcium carbonate) is heated to high temperatures (calcination), which converts it into lime (calcium oxide) and releases carbon dioxide. This statement is also correct.

Explanation of why option B is the correct answer:

While Statements II and III are both correct, only Statement III directly explains Statement I. Statement III describes the calcination process where limestone is converted to lime releasing CO2, directly linking it to the cement industry's carbon emissions. Statement II provides information about the raw materials used, but it does not directly explain the carbon emissions.

Therefore, options A and C are incorrect as they suggest both or one statement explains statement I, but only Statement III does. Option D is incorrect because Statements II and III are both correct.

Explanation

Let's analyze each pair:

I. Cassava : Woody shrub — Correct Cassava (Manihot esculenta) is a perennial woody shrub native to South America. It is cultivated for its edible starchy tuberous root.

II. Ginger : Herb with pseudostem — Correct Ginger (Zingiber officinale) is a herbaceous plant. What appears to be a stem is actually a pseudostem formed by the rolled bases of the leaves.

III. Malabar spinach : Herbaceous climber — Correct Malabar spinach (Basella alba) is a fast-growing, soft-stemmed, perennial vine (climber) with succulent, herbaceous stems.

IV. Mint : Annual shrub — Incorrect Mint (Mentha spp.) is not a shrub. It is a perennial herb, not an annual shrub. Shrubs are woody, but mint is a soft-stemmed herb.

V. Papaya : Woody shrub — Incorrect Papaya (Carica papaya) is technically a large herbaceous plant, not a woody shrub. Its stem is soft and hollow, not woody.

Therefore, only three pairs are correctly matched.

Explanation

Statement I: Correct Direct Air Capture (DAC) is a technology that captures carbon dioxide (CO₂) directly from the atmosphere. The captured CO₂ can then be stored underground (carbon sequestration) or utilized in various industrial processes. Thus, DAC is indeed a method of carbon sequestration.

Statement II: Correct Captured CO₂ from DAC can be used as a feedstock in the production of plastics (such as polycarbonates and polyurethanes) and in food processing (for example, carbonation of beverages and as a preservative). Therefore, DAC can be valuable in both plastic production and food processing industries.

Statement III: Correct In aviation, synthetic fuels (also called e-fuels) can be produced by combining captured CO₂ with hydrogen (produced via electrolysis using renewable energy). This process creates synthetic hydrocarbons that can be used as low-carbon aviation fuels. Thus, DAC can provide the carbon source for such fuels.

Therefore, all three statements are correct.