Solved UPSC Prelims Environment PYQs With Explanation 2025
1. Consider the following statements:
Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions.
Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement.
Statement III: Limestone is converted into lime during clinker production for cement manufacturing.
Which one of the following is correct in respect of the above statements?
(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct
1. Ans-a
Explanation
Global cement manufacturing produced 1.6 billion metric tonnes of CO2 in 2022, the latest year for which there are figures – that’s about 8% of the world’s total CO2 emissions.
Statement 1 is correct
The cement-making process can be divided into two basic steps:
Clinker (the main constituent of cement) is first made in a kiln with gas up to 2000°C, which heats raw materials such as limestone (calcium carbonate) with small quantities of other materials (e.g. clay) to 1,450°C. During this process, known as calcination, the calcium carbonate (limestone) is transformed into calcium oxide (lime), which then reacts with the other constituents from the raw material to form new minerals, collectively called clinker. This near-molten material is rapidly cooled to a temperature of 100 – 200°C.
Clinker is the primary component in cement and is extremely carbon-intensive, making up 90% of overall emissions from cement.
Clinker is then ground with gypsum and other materials to produce the grey powder known as cement.
Both Statement II and Statement III are correct and both of them explain Statement I
2. Consider the following statements:
Statement I: At the 28th United Nations Climate Change Conference (COP28), India refrained from signing the ‘Declaration on Climate and Health’.
Statement II: The COP 28 Declaration on Climate and Health is a binding declaration; and if signed, it becomes mandatory to decarbonize health sector.
Statement III: If India’s health sector is decarbonized, the resilience of its health-care system may be compromised.
Which one of the following is correct in respect of the above statements?
(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of the them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct
2. Ans-c
Explanation
The COP28 Declaration on Climate and Health is a non-binding, non-negotiated call to action and collective commitment that reflects the concerns and common position of countries on the importance of health within climate discourse and in the COP process
Statement 2 is incorrect
India has refused to sign the COP28 Declaration on Climate and Health, India cited the lack of practicality in curbing greenhouse gases use for cooling in the health sector, as the reason.
India expressed concerns that greenhouse gas reduction for cooling in the health sector could hinder its ability to meet the growing demands for medical services, particularly in remote and underserved areas
Only Statements III is correct and that explains Statement I
3. Consider the following statements: Statement
Statement I: Scientific studies suggest that a shift is taking place in the Earth’s rotation and axis.
Statement II: Solar flares and associated coronal mass ejections bombarded the Earth’s outermost atmosphere with tremendous amount of energy.
Statement III: As the Earth’s polar ice melts, the water tends to move towards the equator.
Which one of the following is correct in respect of the above statements?
(a) Both Statements II and III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statement II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct
3. Ans-b
Explanation
Climate change is causing significant shifts in Earth’s rotation and axis. As polar ice melts and water flows towards the equator, it’s altering the planet’s mass distribution and slowing its rotation, leading to slightly longer days
Statements 1 & 3 are correct
Solar flares are huge explosions of electromagnetic radiation from the Sun. A flare appears as a sudden, intense brightening of a region on the Sun, lasting several minutes to hours.
Flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts.
Although solar flares can bombard Earth’s outermost atmosphere with tremendous amounts of energy, most of that energy is reflected back into space by the Earth’s magnetic field or radiated back to space as heat by the thermosphere.
Statement 2 is correct, but does not explain statement 1
4. Consider the following statements:
Statement I: Article 6 of the Paris Agreement on climate change is frequently discussed in global discussions on sustainable development and climate change.
Statement II: Article 6 of the Paris Agreement on climate change sets out the principles of carbon markets.
Statement III: Article 6 of the Paris Agreement on climate change intends to promote inter-country non-market strategies to reach their climate targets.
Which one of the following is correct in respect of the above statements?
(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct
4. Ans-a
Explanation
Article 6 of the Paris Agreement sets out the principles for carbon markets.
Article 6.2 It enables countries to make mutual agreements that permit them to generate and transfer emission reduction units—known as Internationally Transferred Mitigation Outcomes (ITMOs).
Article 6.4 establishes a global carbon market overseen by the UN body called “Article 6.4 Supervisory Body”. It’s a multilateral mechanism that replaces the old Clean Development Mechanism, thus effectively establishing an international carbon market within the scope of the Paris Agreement.
Article 6.8 Non-market mechanisms refer to strategies that are not based on offset markets or emissions trading and include ways other than utilizing carbon markets for cooperation to reduce emissions and fulfil NDCs. These may include technology transfer, capacity building, policy support, mitigation and adaptation finance.
Advocates of NMAs have often argued that marketbased approaches under Article 6.2 and 6.4 do not serve any purpose on mitigation as offsetting does not seek to achieve overall emission reductions. Meanwhile, if any mitigation action has to be supported through cooperative action, it could only come through non-market approaches.
Both statements 2 &3 are correct and both of them explain Statement I
5. Which one of the following launched the ‘Nature Solutions Finance Hub for Asia and the Pacific’?
(a) The Asian Development Bank (ADB)
(b) The Asian Infrastructure Investment Bank (AIIB)
(c) The New Development Bank (NDB)
(d) The International Bank for Reconstruction and Development (IBRD)
5. Ans-a
Explanation
The Asian Development Bank (ADB) launched a Nature Solutions Finance Hub for Asia and the Pacific at COP28, which aims to attract at least $2 billion into investment programs that incorporate nature-based solutions, particularly focused on capital markets and other sources of private capital.
6. With reference to ‘Direct Air Capture’, an emerging technology, which of the following statements is/are correct?
I. It can be used as a way of carbon sequestration.
II. It can be a valuable approach for plastic production and in food processing.
III. In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel.
Select the correct answer using the code given below.
(a) I and II only
(b) III only
(c) I, II and III
(d) None of the above statements is correct
6. Ans-c
Explanation
Direct air capture is a technology that uses chemical reactions to pull carbon dioxide out of air. When air moves over these chemicals, they selectively react with and trap CO2, allowing the other components of air to pass through.
Hence statement 1 is correct
The captured CO2 can be used as a feedstock for various carbon-based materials. It can be used in the production of cement, plastics, carbon fibers, and other industrial applications.
The captured carbon dioxide is able to be used in industrial processes, from carbonating drinks through to the manufacture of synthetic fuel
Hence statements 2 and 3 are correct
7. Regarding Peacock tarantula (Gooty tarantula), consider the following statements:
I. It is an omnivorous crustacean.
II. Its natural habitat in India is only limited to some forest areas.
III. In its natural habitat, it is an arboreal species.
Which of the statements given above is/are correct?
(a) I only
(b) I and III
(c) II only
(d) II and III
7. Ans-d
Explanation
Peacock tarantula (Gooty tarantula) belongs to Arachnida, its not a crustacean
Hence statement 1 is correct
The gooty sapphire ornamental tarantula (Poecilotheria metallica), known for its striking blue coloration, is a highly sought-after species in the global invertebrate pet market, this tarantula is renowned for its vivid metallic blue body, contrasting black markings, and orange or red accents on its legs.
Its naturally found in Seshachalam Biosphere Reserve in the Eastern Ghats of India
In 1899, it was found in a railway timber yard in Gooty, Andhra Pradesh. Hence the name Gooty Tarantula
Hence statements 2 and 3 are correct
The genus Poecilotheria belongs to the family Theraphosidae and is made up of arboreal species of spiders, which are known to occur in India and Sri Lanka. The genus is represented by eight species in India and seven in Sri Lanka.
8. Consider the following statements:
I. Carbon dioxide (CO2) emissions in India are less than 0.5 t CO2/ capita.
II. In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region.
III. Electricity and heat producers are the largest source of CO2 emissions in India.
Which of the statements given above is/are correct?
(a) I and III only
(b) II only
(c) II and III only
(d) I, II and III
8.Ans-c
Explanation
CO2 emissions per capita in India 1.776tCO2 / Capita
Hence statement 1 is incorrect
In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region after China.
Hence statement 2 is correct
CO2 emissions by sector, India
Electricity and Heat producers – 53%
Transport -13%
Industry sector -24%
Residential – 4%
Hence statement 3 is correct
9. Consider the following pairs:
Plant Description
I. Cassava : Woody shrub
I. Ginger : Herb with pseudostem
III. Malabar spinach : Herbaceous climber
IV. Mint : Annual shrub
V. Papaya : Woody shrub
How many of the above pairs are correctly matched?
(a) Only two
(b) Only three
(c) Only four
(d) All the five
9. Ans-b
Explanation
Cassava : Manihot esculenta Crantz. (Euphorbiaceae) also called Cassava, manioc, yuca, balinghoy, mogo, mandioca, kamoteng kahoy, tapioca is a perennial woody shrub in the Euphorbiaceae (spurge family) native to South America but now grown in tropical and subtropical areas worldwide for the edible starchy roots (tubers), which are a major food source in the developing world. This food plant is also medicinally used to treat hypertension, headache, and other pains, irritable bowel syndrome and fever
Hence 1st pair is correctly matched
Ginger: The ginger plant is an erect herbaceous perennial growing from one to three feet in height. The stem is surrounded by the sheathing bases of the two-ranked leaves. The plant is erect, aerial shoots (pseudostem) with leaves, and an underground stem (rhizome). The fleshy and fibrous roots of ginger have indefinite growth from the base of the sprouts.
Hence 2nd pair is correctly matched
Malabar spinach: Malabar spinach, Basella alba, is a herbaceous green leafy vegetable. This fast-growing plant is a soft-stemmed, twining vine that can grow up to 10 feet long as an annual (longer as a perennial) but generally remains smaller in most gardens.
Hence 3rd pair is correctly matched
Mint : Mint is a herbaceous plant of the family Lamiaceae. It is distributed worldwide. The herb as a whole, its essential oils, or major chemical constituents are used for their flavor in various types of foods, confectionary, food preservatives, and antimicrobial agents to control the food-borne pathogens besides their usage in cosmetics and healthcare
Hence 4th pair is incorrectly matched
Papaya : Papayas are fast growing, woody, tree-like plants. It is a large herbaceous plant, usually with a single, straight trunk which can reach to 30 feet.
Hence 5th pair is incorrectly matched
10. With reference to the planet Earth, consider the following statements:
I. Rain forests produce more oxygen than that produced by oceans.
II. Marine phytoplankton and photo-synthetic bacteria produce about 50% of world’s oxygen.
III. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air.
Which of the statements given above is/are correct?
(a) I and II
(b) II only
(c) I and III
(d) None of the above statements is correct
10. Ans-b
Explanation
The ocean generates 50 percent of the oxygen we need, absorbs 30 percent of all carbon dioxide emissions and captures 90 percent of the excess heat generated by these emissions. It is not just ‘the lungs of the planet’ but also its largest ‘carbon sink’ – a vital buffer against the impacts of climate change.
Hence statement 1 is incorrect
Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth. But this little bacteria produces up to 20% of the oxygen in our entire biosphere.
Hence statement 2 is correct
Well-oxygenated surface water may only contain around 8 mg O2/l, while the air contains 210 mg O2/l.
The oxygen content in ocean water is highest at the surface for two primary reasons: this is where oxygen from the atmosphere dissolves into the ocean, and it is also the location where oxygen is produced by phytoplankton during photosynthesis. While respiration occurs in surface waters as well, the rate of oxygen production through photosynthesis exceeds the rate of oxygen consumption via respiration. It is important to note that despite the higher levels of dissolved oxygen at the surface, the concentration of oxygen in water is still significantly lower than that found in the air.
Hence statement 3 is incorrect
11. Which organization has enacted the Nature Restoration Law (NRL) to tackle climate change and biodiversity loss?
(a) The European Union
(b) The World Bank
(c) The Organization for Economic Cooperation and Development
(d) The Food and Agriculture Organization
11. Ans-a
Explanation
The Nature Restoration Regulation is the first continent-wide, comprehensive law of its kind. It is a key element of the EU Biodiversity Strategy, which sets binding targets to restore degraded ecosystems, in particular those with the most potential to capture and store carbon and to prevent and reduce the impact of natural disasters.
12. Consider the following statements :
Statement I: Of the two major ethanol producers in the world, i.e., Brazil and the United States of America, the former produces more ethanol than the latter.
Statement II: Unlike in the United States of America where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil.
Which one of the following is correct in respect of the above statements?
(a) Both Statement I and Statement II are correct and Statement II explains Statement I
(b) Both Statement I and Statement II are correct but Statement II doesnot explain Statement I
(c) Statement I is correct but Statement II is not correct
(d) Statement I is not correct but Statement II is correct
12. Ans-d
Explanation
United States is the world’s largest producer of ethanol, having produced over 15 billion gallons in 2021 and 2022. Together, the United States and Brazil produce 80% of the world’s ethanol. The vast majority of U.S. ethanol is produced from corn, while Brazil primarily uses sugarcane.
Hence statement 1 is incorrect & statement 2 is correct
13. The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report?
I. Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.
II. The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.
Select the correct answer using the code given below.
(a) I only
(b) II only
(c) Both I and II
(d) Neither I nor II
13. Ans-c
Explanation
A report by the World Bank cautioned that India could become one of the first places in the world where wet-bulb temperatures could soar past the survivability threshold of 35°C
What is wet bulb temperature ?
Wet bulb temperature is a meteorological term used to describe the lowest temperature that can be reached by evaporating water into the air at constant pressure. It is measured by covering a thermometer bulb with a wet cloth and letting the water evaporate. As the water evaporates, it cools the thermometer, showing the wet bulb temperature.
This temperature helps measure humidity and understand how much water can evaporate into the air, affecting things like comfort, farming and weather patterns.
A wet-bulb temperature of 35 degrees Celsius is suggested as the maximum safe limit, according to a 2010 study. 35 degree Celsius wet-bulb is an upper limit for mammals, including humans .
High heat combined with humidity poses a greater risk to human health than high heat alone because sweat does not evaporate effectively, leading to increased body temperature, heat exhaustion and potentially fatal heatstroke.
Hence statement 2 is correct
Extended periods of heat waves lead to signicant drying of soil over large regions. Aside from the obvious agricultural implications, this can impact the monsoon onset and can negatively affect agriculture, water security, and even lead to localized flooding, where heavy rain hits dry soil that is unable to absorb it.
Owing to its Peninsular shape surrounded by the Bay of Bengal in the east and the Arabian Sea in the west, the tropical cyclones in India also originate in these two important locations. Though most of the cyclones originate between 10°-15° north latitudes during the monsoon season, yet in case of the Bay of Bengal, cyclones mostly develop during the months of October and November. Here, they originate between 16°-2°° N latitudes and to the west of 92° E. By July the place of origin of these storms shifts to around 18° N latitude and west of 90°E near the Sunderban Delta.
It was mentioned that the energy to the tropical cyclone comes from the latent heat released by the warm moist air. Hence, with the increase in distance from the sea, the force of the cyclone decreases. In India, the force of the cyclone decreases with increase in distance from the Bay of Bengal and the Arabian Sea. So, the coastal areas are often struck by severe cyclonic storms with an average velocity of 180 km/h. Often, this results in abnormal rise in the sea level known as Storm Surge.
Hence statement 2 is correct