Air pollution and emissions — UPSC Prelims PYQs
27 questions in this bank come from Air pollution and emissions, spanning UPSC Prelims papers from 2011 to 2025. Every question here carries all four options, the correct answer and a full explanation.
It has appeared in 13 of the last 16 papers, most heavily in 2025 with 5 questions. That makes it one of the most dependable areas in the paper.
The themes examined most often within it are Emissions from various sources (5), Environmental dynamics and pollution (5), Air quality standards and guidelines (4), Sources and effects of air pollutants (4) and Health impacts of air pollution (2). Those counts are of questions in which the theme is examined, not merely mentioned.
Questions here are spread across Environment & Ecology (22), General Studies (Uncategorized) (2), Economy (1) and Geography (1). Between them they draw on 28 distinct themes, so this is a broader area than a single revision note can cover. That is 1.9% of the 1433 questions in the bank — useful for deciding how much revision time it deserves.
It has come up more often lately — roughly 2.4 questions a year across the last five papers, against 1.5 before that.
It was not examined in 3 of those papers. Each question below links to its full explanation and to related questions on the same theme from other years, so a weak area can be worked through in one pass rather than hunted for paper by paper.
UPSC Prelims 20255 questions
- Environment & Ecology
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 sources of CO2 emissions in India. Which of the statements given above is/are correct?
- Economy
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?
- General Studies (Uncategorized)
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 photosynthetic 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 are correct?
- Geography
Consider the following statements: Statement I: The amount of dust particles in the atmosphere is more in subtropical and temperate areas than in equatorial and polar regions. Statement II: Subtropical and temperate areas have less dry winds. Which one of the following is correct in respect of the above statements?
- Environment & Ecology
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?
UPSC Prelims 20243 questions
- Environment & Ecology
According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
- Environment & Ecology
Which one of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen?
- General Studies (Uncategorized)
Consider the following: 1. Pyroclastic debris 2. Ash and dust 3. Nitrogen compounds 4. Sulphur compounds How many of the above are products of volcanic eruptions?
UPSC Prelims 20231 question
UPSC Prelims 20222 questions
- Environment & Ecology
Consider the following: 1. Carbon monoxide 2. Nitrogen oxide 3. Ozone 4. Sulphur dioxide Excess of which of the above in the environment is/are cause(s) of acid rain?
- Environment & Ecology
In the context of WHO Air Quality Guidelines, consider the following statements: 1. The 24-hour mean of PM2.5 should not exceed 15 ug/ m3 and annual mean of PM2.5 should not exceed 5 ug/ m3. 2. In a year, the highest levels of ozone pollution occur during the period of inclement weather. 3. PM10 can penetrate the lung barrier and enter the bloodstream. 4. Excessive ozone in the air can trigger asthma. Which of the statements given above are correct?
UPSC Prelims 20211 question
UPSC Prelims 20202 questions
- Environment & Ecology
Consider the following statements: 1. Coal ash contains arsenic, lead and mercury. 2. Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment. 3. High ash content is observed in Indian coal. Which of the statements given above is/are correct?
- Environment & Ecology
Which of the following are the reasons/factors for exposure to benzene pollution? 1. Automobile exhaust 2. Tobacco smoke 3. Wood burning 4. Using varnished wooden furniture 5. Using products made of polyurethane Select the correct answer using the code given below:
UPSC Prelims 20194 questions
- Environment & Ecology
Consider the following statements: 1. Agricultural soils release nitrogen oxides into the environment. 2. Cattle release ammonia into the environment. 3. Poultry industry releases reactive nitrogen compounds into the environment. Which of the statements given above is/are correct?
- Environment & Ecology
Which of the following statements are correct about the deposits of ‘methane hydrate’? 1. Global warming might trigger the release of methane gas from these deposits. 2. Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the seafloor. 3. Methane in the atmosphere oxidised to carbon dioxide after a decade or two. Select the correct answer using the code given below.
- Environment & Ecology
Consider the following statements: The Environment Protection Act, 1986 empowers the Government of India to: 1. State the requirement of public participation in the process of environmental protection, and the procedure and manner in which it is sought 2. Lay down the standards for emission or discharge of environmental pollutants from various sources Which of the statements given above is/are correct?
- Environment & Ecology
Consider the following: 1. Carbon monoxide 2. Methane 3. Ozone 4. Sulphur dioxide Which of the above are released into the atmosphere due to the burning of crop/biomass residue?
UPSC Prelims 20171 question
UPSC Prelims 20161 question
UPSC Prelims 20142 questions
- Environment & Ecology
There is some concern regarding the nanoparticles of some chemical elements that are used by the industry in the manufacture of various products. Why? 1. They can accumulate in the environment and contaminate water and soil. 2. They can enter the food chains. 3. They can trigger the production of free radicals. Select the correct answer using the code given below.
- Environment & Ecology
Which of the following are some important pollutants released by steel industry in India? 1. Oxides of sulphur 2. Oxide of nitrogen 3. Carbon monoxide 4. Carbon dioxide Select the correct answer using the code given below.
UPSC Prelims 20132 questions
UPSC Prelims 20122 questions
- Environment & Ecology
Consider the following statements: Chlorofluorocarbons, known as ozone-depleting substances, are used: 1. In the production of plastic foams. 2. In the production of tubeless tyres. 3. In cleaning certain electronic components. 4. As pressurizing agents in aerosol cans. Which of the statements given above is/are correct?
- Science & Technology
Biomass gasification is considered to be one of the susta- inable 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 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:
