UPSC Prelims · Environment & Ecology PYQ
Solar energy, biofuels, waste-to-energy technologies, and sustainable materials and construction practices.
Includes
Consider the following statements:
Statement I: Circular economy reduces the emissions of greenhouse gases.
Statement II: Circular economy reduces the use of raw materials as inputs.
Statement III: Circular economy reduces wastage in the production process.
Which one of the following is correct in respect of the above statements?
Correct answer: A. Both Statement II and Statement III are correct and both of them explain Statement I
Explanation
A circular economy reduces greenhouse gas emissions — Statement I is correct, explained by both following statements. It reduces reliance on raw material inputs through reuse and recycling — Statement II is correct. It also reduces wastage in production processes by keeping materials in use longer — Statement III is correct, and both these resource-efficiency effects together explain the emissions reduction.
With reference to India's preparation for Climate-Smart Agriculture, consider the following statements:
Correct answer: B. The project of CCAFS is carried out under the Consultative Group on International Agricultural Research (CGIAR) headquartered in France
Explanation
The CCAFS project (which runs India's Climate-Smart Village approach) operates under CGIAR, whose headquarters are located in France (Montpellier), making this pairing the correct statement among the options, since the other options either misattribute the leading organisation or restate facts already covered by option (b) and (c) separately, with 'All of the above' not being accurate given option (a)'s imprecise framing.
Consider the following heavy industries :
1. Fertilizer plants
2. Oil refineries
3. Steel plants Green hydrogen is expected to play a significant role in decarbonizing how many of the above industries?
Correct answer: C. All three
Explanation
Green hydrogen is expected to play a significant decarbonisation role in fertiliser production (replacing grey hydrogen in ammonia synthesis), oil refining (replacing hydrogen currently sourced from fossil fuels), and steel manufacturing (as a reducing agent replacing coking coal) — all three heavy industries.
Consider the following statements:
1. Gujarat has the largest solar park in India.
2. Kerala has a fully solar powered International Airport.
3. Goa has the largest floating solar photovoltaic project in India.
Which of the statements given above is/are correct?
Correct answer: B. 2 only
Explanation
Kerala's Cochin International Airport is indeed the world's first fully solar-powered airport — Statement 2 is correct. However, Rajasthan (Bhadla Solar Park), not Gujarat, hosts India's largest solar park, making Statement 1 incorrect. India's largest floating solar photovoltaic project has been developed in other states, not Goa, making Statement 3 incorrect.
Steel slag can be the material for which of the following ?
Correct answer: D. 1, 2 and 3
Explanation
Steel slag, a byproduct of steel manufacturing, can be repurposed as material for road construction, cement production, and land reclamation/fill applications, among other uses, supporting industrial waste recycling.
In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint?
1. Copper slag
2. Cold mix asphalt technology
3. Geotextiles
4. Hot mix asphalt technology
5. Portland cement
Select the correct answer using the code given below:
Correct answer: A. 1, 2 and 3 only
Explanation
Copper slag, cold mix asphalt technology, and geotextiles are all preferred in rural road construction for their lower carbon footprint and effective use of waste materials, unlike hot mix asphalt (energy-intensive heating) or plain Portland cement, which have higher associated emissions.
According to India's National Policy on Biofuels, which of the following can be used as raw material for the production of biofuels?
1. Cassava
2. Damaged wheat grains
3. Groundnut seeds
4. Horse gram
5. Rotten potatoes
6. Sugar beet
Select the correct answer using the code given below:
Correct answer: A. 1, 2, 5 and 6
Explanation
India's National Policy on Biofuels permits using damaged food grains, rotten potatoes, and surplus starch/sugar-based feedstocks like cassava and sugar beet as raw materials for biofuel production, provided they do not compete with the food supply chain in edible form; groundnut seeds and horse gram are not specified biofuel feedstocks under this policy.
In the context of which one of the following are the terms ‘pyrolysis’ and ‘plasma gasification’ mentioned?
Correct answer: D. Waste-to-energy technologies
Explanation
Pyrolysis and plasma gasification are advanced waste-to-energy technologies that convert solid waste into energy or usable byproducts through controlled thermal decomposition processes.
'Net metering' is sometimes seen in the news in the context of promoting the
Correct answer: A. production and use of solar energy by the households/consumers
Explanation
Net metering allows households and consumers who generate their own solar power to feed excess electricity back into the grid and receive credit, promoting rooftop solar energy adoption.
On which of the following can you find the Bureau of Energy Efficiency Star Label?
1. Ceiling fans
2. Electric geysers
3. Tubular fluorescent lamps
Select the correct answer using the code given below:
Correct answer: D. 1 and 3
Explanation
The Bureau of Energy Efficiency Star Label is applied to appliances such as ceiling fans and tubular fluorescent lamps to indicate their energy efficiency rating; electric geysers were not covered under this labelling scheme at the time referenced.
Biomass gasification is considered to be one of the sustainable solutions to the power crisis in India. In this context, which of the following statements is/are correct?
1. Coconut shells, groundnut shells and rice husk can be used in biomass gasification.
2. The combustible gases generated from biomass gasification consist of hydrogen and carbon-dioxide only.
3. The combustible gases generated from biomass gasification can be used for direct heat generation but not in internal combustion engines.
Select the correct answer using the codes given below :
Correct answer: A. 1 only
Explanation
Biomass materials like coconut shells, groundnut shells, and rice husk can indeed be used in biomass gasification — Statement 1 is correct. However, the combustible gases produced include not just hydrogen and carbon dioxide but also carbon monoxide and methane, making Statement 2 incorrect. These gases can also be used to power internal combustion engines, not just for direct heat generation, making Statement 3 incorrect as well.
In the Union Budget 2011-12, a full exemption from the basic customs duty was extended to the bio-based asphalt (bioasphalt). What is the importance of this material?
1. Unlike traditional asphalt, bio-asphalt is not based on fossil fuels.
2. Bioasphalt can be made from non-renewable resources.
3. Bioasphalt can be made from organic waste materials.
4. It is eco-friendly to use bioasphalt for surfacing of the roads.
Which of the statements given above are correct?
Correct answer: B. 1, 3 and 4 only
Explanation
Bioasphalt is not based on fossil fuels, unlike traditional asphalt — Statement 1 is correct. It can be produced from organic waste materials such as sugar, molasses, or vegetable oils — Statement 3 is correct. Its use for road surfacing is considered environmentally friendly given its renewable origin — Statement 4 is correct. However, being derived from organic/renewable sources, it is not made from non-renewable resources, so Statement 2 is incorrect.
Other than Jatropha curcas, why is Pongamia pinnata also considered a good option for the production of bio-diesel in India?
1. Pongamia pinnata grows naturally in most of the arid regions of India.
2. The seeds of Pongamia pinnata are rich in lipid content of which nearly half is oleic acid.
Which of the statements given above is/are correct?
Correct answer: C. Both 1 and 2
Explanation
Pongamia pinnata grows well even in arid and semi-arid regions of India, requiring minimal irrigation — Statement 1 is correct. Its seeds have high lipid content, with a substantial share being oleic acid, making it suitable for biodiesel extraction — Statement 2 is correct.
Given below are the names of four energy crops. Which one of them can be cultivated for ethanol ?
Correct answer: B. Maize
Explanation
Maize is a starch-rich energy crop widely cultivated and processed for ethanol production, unlike Jatropha, Pongamia, or Sunflower, which are primarily used for biodiesel rather than ethanol.
In the context of alternative sources of energy, ethanol as a viable bio-fuel can be obtained from
Correct answer: C. Sugarcane
Explanation
Sugarcane, due to its high sugar content, is a major feedstock used for ethanol production as a biofuel, particularly in countries like Brazil and increasingly in India.
Which one of the following Union Ministries is implementing the Biodiesel Mission (as Nodal Ministry)?
Correct answer: D. Ministry of Rural Development
Explanation
The Ministry of Rural Development served as the nodal ministry implementing India's National Biodiesel Mission, given the rural livelihood linkage of biodiesel feedstock cultivation.
Match List I (Power generation plant) with List II (Feed material) and select the correct answer using the codes given below the Lists:
List I
I. M/s Gowthami Solvents Oil Limited, Andhra Pradesh
II. M/s KM. Sugar Mills, Uttar Pradesh
III. M/s Satia Paper Mills, Punjab
IV. M/s Al Kabeer Exports Limited, Andhra Pradesh
List II
A) Rice husk
B) Slaughter-house waste
C) Distillery spent wash
D) Black liquor
Codes:
Correct answer: C. I-A, II-C, III-D, IV-B
Explanation
Gowthami Solvents Oil Limited uses rice husk as feed material; KM Sugar Mills uses distillery spent wash; Satia Paper Mills uses black liquor (a paper industry byproduct); and Al Kabeer Exports uses slaughterhouse waste for power generation.
Which one of the following fuels causes minimum environmental pollution?
Correct answer: C. Hydrogen
Explanation
Hydrogen, when combusted, produces primarily water vapour as a byproduct, making it the fuel causing minimum environmental pollution among the given options, unlike diesel, coal, or kerosene, which release significant particulate matter and greenhouse gases.