UPSC Environment and Ecology – Chapter 10: Air Pollution (32 MCQs)

← Back

UPSC Environment and Ecology – Chapter 10: Air Pollution (32 MCQs) – 32 questions, subject: Environment. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

Get daily current affairs & exam alerts – follow us YouTube WhatsApp Channel Telegram Channel Facebook Page Instagram
Share with friends & study groups
Link to this page from your website / blog (HTML code)
1.  

Which of the following is a secondary air pollutant?

Correct Answer: D [Ground-level ozone]

Explanation:

Ground-level ozone is not emitted directly; it forms in the air when NOx and hydrocarbons react in sunlight.

2.  

The National Air Quality Index of India was launched in:

Correct Answer: B [2015]

Explanation:

The National Air Quality Index was launched by the Prime Minister on 6 April 2015.

3.  

How many pollutants are covered by India's National Ambient Air Quality Standards, 2009?

Correct Answer: C [12]

Explanation:

The NAAQS notified in 2009 cover 12 pollutants – the eight AQI pollutants plus benzene, benzo(a)pyrene, arsenic and nickel.

4.  

An AQI value of 350 falls in the category:

Correct Answer: B [Very poor]

Explanation:

The 'Very poor' category of the AQI covers values from 301 to 400, so 350 falls in it.

5.  

India's NAAQS limit for the annual average of PM2.5 is:

Correct Answer: A [40 µg/m³]

Explanation:

Under the NAAQS, 2009 the Indian annual standard for PM2.5 is 40 µg/m³ (24-hour: 60 µg/m³).

6.  

A layer of warm air above cooler air near the ground, which traps pollutants, is called:

Correct Answer: B [temperature inversion]

Explanation:

In a temperature inversion a warm layer sits over cold surface air, stopping vertical mixing and trapping pollutants.

7.  

Peroxyacetyl nitrate (PAN) is a component of:

Correct Answer: C [photochemical smog]

Explanation:

Peroxyacetyl nitrate is a secondary oxidant formed with ozone when NO₂ and hydrocarbons react in sunlight.

8.  

India moved to Bharat Stage VI emission norms nationwide from:

Correct Answer: D [1 April 2020]

Explanation:

India leapfrogged from BS-IV to BS-VI emission norms nationwide on 1 April 2020.

9.  

The National Clean Air Programme was launched in:

Correct Answer: A [2019]

Explanation:

The National Clean Air Programme was launched on 10 January 2019.

10.  

The Commission for Air Quality Management deals with:

Correct Answer: D [Delhi–NCR and adjoining areas]

Explanation:

CAQM was created for the National Capital Region and adjoining areas by its 2021 Act and runs GRAP there.

11.  

Assertion (A): Air pollution in north India is worst on calm winter nights.

Reason (R): Temperature inversion and low wind trap pollutants near the ground.

Correct Answer: A [Both A and R are true, and R is the correct explanation of A]

Explanation:

Both true: on calm winter nights an inversion and low wind trap pollutants near the ground, explaining the worst air.

12.  

Consider the following about the WHO Air Quality Guidelines, 2021:

1. The annual mean of PM2.5 should not exceed 5 µg/m³.
2. The 24-hour mean of PM2.5 should not exceed 15 µg/m³.
3. They are legally binding on India.

Which of the statements given above are correct?

Correct Answer: C [1 and 2 only]

Explanation:

guidelines are not binding.

13.  

The Bhopal gas tragedy of 1984 was caused by the leak of:

Correct Answer: A [methyl isocyanate]

Explanation:

On 2–3 December 1984 methyl isocyanate leaked from the Union Carbide pesticide plant at Bhopal.

14.  

The Supreme Court ordered Delhi's buses and autos to switch to CNG in the case:

Correct Answer: B [M. C. Mehta v. Union of India]

Explanation:

In M. C. Mehta v. Union of India the Supreme Court's 1998 order moved Delhi's buses and autos to CNG.

15.  

Flue-gas desulphurisation units in thermal power plants mainly reduce:

Correct Answer: C [sulphur dioxide]

Explanation:

FGD units scrub sulphur dioxide from flue gas, as required by the SO₂ norms for coal-based plants.

16.  

The Pusa decomposer, developed by IARI, is meant to:

Correct Answer: A [break down paddy straw in the field to avoid burning]

Explanation:

IARI's Pusa decomposer is a microbial solution that breaks down paddy straw in the field so it need not be burnt.

17.  

Arrange in chronological order:

1. National AQI launched
2. Air Act
3. National Clean Air Programme
4. Bhopal gas tragedy

Select the correct order:

Correct Answer: C [2-4-1-3]

Explanation:

1981, 1984, 2015, 2019.

18.  

Which one of the following correctly describes classical (London-type) smog, as distinct from photochemical smog?

Correct Answer: A [It forms in cool, humid, foggy air from smoke, soot and sulphur dioxide, and is chemically reducing]

Explanation:

classical smog is a reducing mix of smoke, soot and sulphur dioxide that forms in cool, humid, foggy weather, as in London, 1952.

19.  

In February 2024 the Supreme Court upheld the closure, on pollution grounds, of which copper smelter?

Correct Answer: D [Sterlite Copper, Thoothukudi]

Explanation:

closed in 2018; the Supreme Court upheld the closure in February 2024.

20.  

The Graded Response Action Plan (GRAP) for Delhi–NCR is now run by the:

Correct Answer: D [Commission for Air Quality Management]

Explanation:

a statutory body under its 2021 Act.

21.  
UPSC Prelims 2024

According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?

Correct Answer: D [Power plants using fossil fuels]

Explanation:

The US EPA identifies fossil-fuel combustion at power plants and other industrial facilities as the largest source of SO₂.

22.  
UPSC Prelims 2022

In the context of WHO Air Quality Guidelines, consider the following statements:

1. The 24-hour mean of PM2.5 should not exceed 15 μg/m³ and annual mean of PM2.5 should not exceed 5 μg/m³.
2. In a year, the highest levels of ozone pollution occur during the periods 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?

Correct Answer: B [1 and 4 only]

Explanation:

WHO 2021 sets PM2.5 at 15 (24-hour) and 5 (annual) µg/m³, and ozone can trigger asthma; statements 2 and 3 are false.

23.  
UPSC Prelims 2021

Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?

1. Brakes of motor vehicles
2. Engines of motor vehicles
3. Microwave stoves within homes
4. Power plants
5. Telephone lines

Select the correct answer using the code given below.

Correct Answer: B [1, 2 and 4 only]

Explanation:

Magnetite nanoparticles come from vehicle brakes, engines and power plants, not from microwave stoves or telephone lines.

24.  
UPSC Prelims 2021

Why is there a concern about copper smelting plants?

1. They may release lethal quantities of carbon monoxide into the environment.
2. The copper slag can cause the leaching of some heavy metals into the environment.
3. They may release sulphur dioxide as a pollutant.

Select the correct answer using the code given below.

Correct Answer: B [2 and 3 only]

Explanation:

Copper smelters emit sulphur dioxide and their slag can leach heavy metals; lethal carbon monoxide is not the concern.

25.  
UPSC Prelims 2021

With reference to furnace oil, consider the following statements:

1. It is a product of oil refineries.
2. Some industries use it to generate power.
3. Its use causes sulphur emissions into the environment.

Which of the statements given above are correct?

Correct Answer: D [1, 2 and 3]

Explanation:

Furnace oil is a refinery residue, burnt by some industries for power, and its sulphur causes sulphur emissions.

26.  
UPSC Prelims 2020

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?

Correct Answer: D [1, 2 and 3]

Explanation:

Coal ash contains arsenic, lead and mercury, coal plants emit SO₂ and NOx, and Indian coal is high in ash.

27.  
UPSC Prelims 2020

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:

Correct Answer: A [1, 2 and 3 only]

Explanation:

Automobile exhaust, tobacco smoke and wood burning are recognised sources of benzene exposure in the official key.

28.  
UPSC Prelims 2019

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?

Correct Answer: D [1, 2, 3 and 4]

Explanation:

Burning crop residue releases carbon monoxide, methane, sulphur dioxide and ozone-forming gases.

29.  
UPSC Prelims 2019

Consider the following statements:

1. Agricultural soils release nitrogen oxides into the environment.
2. Cattle release ammonia into the environment.
3. The poultry industry releases reactive nitrogen compounds into the environment.

Which of the statements given above is/are correct?

Correct Answer: D [1, 2 and 3]

Explanation:

Soils release nitrogen oxides, cattle release ammonia and poultry releases reactive nitrogen compounds – all three are true.

30.  
UPSC Prelims 2016

In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of the Air Quality Index?

1. Carbon dioxide
2. Carbon monoxide
3. Nitrogen dioxide
4. Sulphur dioxide
5. Methane

Select the correct answer using the code given below.

Correct Answer: B [2, 3 and 4 only]

Explanation:

Carbon monoxide, nitrogen dioxide and sulphur dioxide are among the eight AQI pollutants; CO₂ and methane are not.

31.  
UPSC Prelims 2014

Which of the following are some important pollutants released by the 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:

Correct Answer: D [1, 2, 3 and 4]

Explanation:

Steel plants emit oxides of sulphur and nitrogen, carbon monoxide and carbon dioxide from coke ovens, sintering and blast furnaces.

32.  
UPSC Prelims 2013

Photochemical smog is a resultant of the reaction among

Correct Answer: A [NO2, O3 and peroxyacetyl nitrate in the presence of sunlight]

Explanation:

Photochemical smog results from NO₂, ozone and PAN reacting in strong sunlight.

➤ Full notes, maps, tables, a reason for every option and Mains PYQs – U18 · Environment and Ecology (UPSC book, ₹249): www.shanmugamiasacademy.in/study-materials/upsc-environment-ecology

📘 U18 · Environment, Ecology, Biodiversity and Climate Change – UPSC Civil Services (Prelims & Mains)
Here you get the answer with a one-line explanation. 24 chapters · 701 MCQs incl. UPSC Prelims PYQs with a reason for every option · 120 Mains questions + Mains PYQs · maps, tables, revision cards
Get the book – ₹249 ₹499 →
Score: 0 Answered: 0 / 0