Questions on Environment and Ecology (Part 2)

In the 2025 Prelims, there were 20 questions on the subject Environment and Ecology. Here are Questions 1-10 with answers. 

Questions 1-10 with Correct Responses, Explanations, and Background Information

Question 1

1. Consider the following types of vehicles:  

1. Full battery electric vehicles  

2. Hydrogen fuel cell vehicles  

3. Fuel cell-electric hybrid vehicles  

How many of the above are considered as alternative powertrain vehicles?  

(a) Only one  

(b) Only two  

(c) All the three  

(d) None  

Correct Response: C

Explanation: In a motor vehicle, the powertrain comprises the main components that generate power and deliver that power to the road surface, water, or air. Alternative powertrains include propulsion systems that are not based exclusively on the internal combustion engine. This definition includes hybrids, full battery electrics, hydrogen fuel cells, and compressed air. All of them produce zero emissions. 

Background information:

·      Full battery electric vehicle is fully powered by electricity from a battery.

·      Hydrogen fuel cell vehicle runs on electrical energy produced by a hydrogen fuel cell.  

·      Fuel cell-electric hybrid vehicle runs on a combination of fuel cell and battery. 

Question 2

2.  Consider the following:  

1. Cigarette butts  

2. Eyeglass lenses  

3. Car tyres  

How many of them contain plastic? 

(a) Only one 

(b) Only two  

(c) All the three  

(d) None 

Correct Response: C

Explanation and Background Information:

Cigarette butts are made of cellulose acetate, a man-made plastic material, and contain hundreds of toxic chemicals. While cigarette filters, or the plastic part of butts, can take up to 10 years to completely degrade, the chemicals they release can remain in the environment for many more years beyond the life of the cigarette butt itself.

Eyeglasses are made of plastic and, when they are polished, a large amount of microplastics are generated. In addition, the wastewater from polishing units contains nanoplastics.

Tyres are made of natural rubber, synthetic rubber, and a range of additives. The synthetic rubber (which could be 20%-24% of a tyre) is made from petroleum and is a type of plastic. When tyres hit the road, they emit many particles including microplastics. Tyre wear represents a large source of microplastics entering the aquatic environment.

Question 3

3. Consider the following substances:  

1. Ethanol 

2. Nitroglycerine  

3. Urea  

Coal gasification technology can be used in the production of how many of them?  

(a) Only one  

(b) Only two  

(c) All the three  

(d) None

Correct Response: B

Explanation and Background Information: Coal gasification converts coal into a gas, which itself is a mixture of gasses such as carbon monoxide, hydrogen, carbon dioxide, methane, and water vapour. This gas is then used to produce synthetic natural gas, methanol, ethanol, and ammonia. In turn, ammonia is used to make urea. Nitroglycerine is not made by coal gasification.

Question 4

4.  Consider the following statements: 

Statement I: Activated carbon is a good and an attractive tool to remove pollutants from effluent streams and to remediate contaminants from various industries. 

Statement II: Activated carbon exhibits a large surface area and a strong potential for adsorbing heavy metals. 

Statement III: Activated carbon can be easily synthesized from environmental wastes with high carbon content.  

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

Correct Response: A

Explanation and Background Information: Activated carbon is often used as a water purifier and the reason is that activated carbon exhibits a large surface area and can thus adsorb heavy metals. Activated carbon can be made from environmental wastes with high carbon content. Thus, both Statement II and Statement III are correct and both of them explain Statement I.  

Question 5

5. 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 COP28 Declaration on Climate and Health is a binding declaration; and if signed, it becomes mandatory to decarbonize the 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 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.

Correct Response: C

Explanation and Background Information: At the 2023 UN Climate Change Conference (COP28), 124 countries signed the 'Declaration on Climate and Health'. The declaration, aimed at addressing the critical intersection between climate change and global health, emphasised the need for swift and substantial reductions in greenhouse gas emissions.

The declaration outlined a commitment to reducing greenhouse gases for cooling applications within healthcare infrastructure - a measure India found difficult to comply with. 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. Hence, India did not sign the Declaration.

Like most other UN declarations, this too was not a binding one.

Thus, Statement II is not correct, while Statement III is correct and explains Statement I, which is also correct.

Question 6

6. 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  

Correct Response: A

Explanation and Background Information: According to UN Development Programme, state funds will not be enough to finance the Nationally Determined Contributions (NDCs) of the developing countries. Most emission reduction activities need to be implemented and financed by the private sector. Suitable finance approaches are therefore required – and this is where Article 6 of the Paris Agreement can help.

Article 6 acknowledges that countries can pursue voluntary cooperation in the implementation of their NDCs to allow for higher mitigation ambition and to promote sustainable development. Article 6.2 outlines the possibility of cooperative approaches and the transfer of Internationally Transferrable Mitigation Outcomes (ITMOs) between different actors, including countries and private sector companies, through bilateral agreements. ITMOs use a carbon dioxide equivalent (CO2e) metric for a new set of market provisions or other greenhouse gas mitigation outcomes that are defined under Article 6.2 of the Paris Agreement. Articles 6.2 and 6.4 lay down the principles of carbon markets.  

The mechanisms set out under Article 6.2 on cooperative approaches also underline that beyond emissions reductions, climate mitigation projects can directly or indirectly yield many development benefits – including job creation, technology transfer to increase access to energy, support to livelihoods and food security, gender empowerment and more.

Article 6.8 promotes non-market approaches, including initiatives such as capacity building, technology transfer, policy coordination, and financial support, enabling countries to pursue climate goals through cooperation that does not involve trading of carbon credits.

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

Question 7

7. 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) 

Correct Response: A

Explanation and Background Information: The Asian Development Bank launched in 2023 the Nature Solutions Finance (NSF) Hub. The project specifically focuses on catalyzing finance into Nature-based Solutions (NbS) to support nature-based climate actions and biodiversity conservation. Its establishment is an opportunity to develop innovative solutions to address the intertwined crises of nature and climate. The NSF Hub's goal is to increase investments in NbS projects across Asia and the Pacific by proactively developing scalable and bankable demonstration projects by creating a platform with practical NbS solutions centered around innovative finance approaches. It aims to do this through a partnership approach with global development entities in the nature space along with concessional fund sources who can work together with ADB under a focused roadmap of activities.

Question 8

8. With reference to 'Direct Air Capture' (DAC), which of the following statements is/are correct? 

1. It can be used as a way of carbon sequestration. 

2. It can be a valuable approach for plastic production and in food processing. 

3. 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 codes given below. 

(a) 1 and 2 only  

(b) 3 only  

(c) 1, 2, and 3  

(d) None of the above statements is correct. 

Correct Response: C

Explanation and Background Information: Direct Air Capture (DAC) technologies extract CO2 directly from the atmosphere at any location, unlike carbon capture which is generally carried out at the point of emissions, such as a steel plant. Mimicking what already occurs in nature, DAC essentially involves industrial photosynthesis, harnessing the power of the sun to draw carbon directly out of the atmosphere.

Capturing CO2 from the air is the most expensive application of carbon capture. The CO2 in the atmosphere is much more dilute than in, for example, flue gas from a power station or a cement plant. This contributes to DAC’s higher energy needs and costs relative to these applications. By harnessing excess energy generated by renewables, DAC systems can operate more efficiently and cost-effectively.

What do we do with the captured CO2?

·      The CO2 can be permanently stored in deep geological formations or used for a variety of applications.

·      Early commercial efforts to develop synthetic aviation fuels using air-captured CO2 and hydrogen have started, reflecting the important role that these fuels could play in the sector.

·      Coca-Cola aims to use DAC to source CO2 for its carbonated beverages.

·      Injecting CO2 into cement as it’s being manufactured strengthens the mixture and produces a far sturdier end-product. This process also permanently sequesters CO2 into cement, largely offsetting the material’s high footprint.

According to the futurist and entrepreneur Peter Diamandis:

“DAC will soon allow us to sequester gigatons of CO2 from the atmosphere, yielding material abundance for countless everyday products. By making CO2 a vital part of our economy, we can begin to derive incredible value from one of our principal climate change agents, currently emitted as a “waste” product.

Applications of captured carbon are near-limitless. Whether for fuel on Mars, smart city infrastructural equipment, or everyday plastic commodities, our atmosphere’s carbon reserves are free for the taking and will fundamentally transform our global energy and materials economy.”

Since all the three Statements mention how DAC “can” be used, all of them are correct.

Question 9

9. Regarding Peacock tarantula (Gooty tarantula), consider the following statements:  

1. It is an omnivorous crustacean. 

2. Its natural habitat in India is only limited to some forest areas. 

3. In its natural habitat, it is an arboreal species. 

Which of the statements given above is/are correct?  

(a) 1 only  

(b) 1 and 2 only  

(c) 2 only 

(d) 2 and 3 only 

Correct Response: D

Explanation and Background Information:

·      The Peacock tarantula is a spider, with stunning blue legs and a bright, yellow-striped abdomen, making it look like a magical creature from a fairy tale. It is not a crustacean.

·      It feeds primarily on insects and other small invertebrates. It is not omnivorous.

·      It is found in a very small area in southeastern India, particularly in the deciduous forests of Andhra Pradesh. It was first discovered in a small forest near the town of Gooty in Andhra Pradesh and hence it is called Gooty Sapphire tarantula.

·      It lives in the forest and so it is arboreal.

·      Its distribution is extremely limited and is hence one of the most endangered tarantulas in the world due to habitat loss and deforestation.

Thus, Statements II and II are correct.

Question 10

10. Consider the following statements:  

1. Carbon dioxide (CO2) emissions in India are less than 0.5 t CO2/ capita.  

2. In terms of CO2 emissions from fuel combustion, India ranks second in the Asia-Pacific region.  

3. Electricity and heat producers are the largest sources of СО2 emissions in India.  

Which of the statements given above is/are correct?  

(a) 1 and 3 only  

(b) 2 only 

(c) 2 and 3 only  

(d) I, 2, and 3 

Correct Response: C

Explanation and Background Information:

·      India’s per capita CO2 emissions amount to approximately 2 tonnes in 2023

·      India is the second-largest emitter of CO₂ from fuel combustion in the Asia-Pacific region, after China. This is due to our dependence on coal-based power.

Thus, Statements II and II are correct.

(Note: Questions 11-20 will be covered in the next two posts.)