Question

UPSC Prelims 2022 Question:

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?

  1. 1. 1, 2 and 3
  2. 2. 2 and 4 only
  3. 3. 4 only
  4. 4. 1, 3 and 4

Answer (Detailed Solution Below)

Option 2: 2 and 4 only

Detailed Solution

Explanation: 

  • Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth’s surface. Oxides of nitrogen and sulphur which are acidic in nature can be blown by wind along with solid particles in the atmosphere and finally settle down either on the ground as dry deposition or in water, fog and snow as wet deposition.

  • Burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power stations and furnaces or petrol and diesel in motor engines produce sulphur dioxide and nitrogen oxides. SO2 and NO2 after oxidation and reaction with water are major contributors to acid rain, because polluted air usually contains particulate matter that catalyse the oxidation.

Therefore, option (2) is the correct answer.

Subject: Environment|Pollution

Latest UPSC Exam 2026 Updates

Last updated on March, 2026

UPSC Final Result 2025 is now out.

→ UPSC has released UPSC Toppers List 2025 with the Civil Services final result on its official website.

Anuj Agnihotri secured AIR 1 in the UPSC Civil Services Examination 2025.

UPSC Marksheet 2025 is now out.

UPSC Notification 2026 & UPSC IFoS Notification 2026 is now out on the official website at upsconline.nic.in.

UPSC Calendar 2026 has been released.

→ Check out the latest UPSC Syllabus 2026 here.

UPSC Prelims 2026 will be conducted on 24th May, 2026 & UPSC Mains 2026 will be conducted on 21st August 2026.

→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.

→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2026 featuring full-length mock tests, detailed solutions, and performance analysis.

→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.

→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.

Shakti Dubey secures AIR 1 in UPSC CSE Exam 2024.

→ Also check Best UPSC Coaching in India

Vajiram Content Team
Vajiram Content Team
UPSC GS Course 2026
UPSC GS Course 2026
₹1,75,000
Enroll Now
GS Foundation Course 2 Yrs
GS Foundation Course 2 Yrs
₹2,45,000
Enroll Now
UPSC Mentorship Program
UPSC Mentorship Program
₹85000
Enroll Now
UPSC Sureshot Mains Test Series
UPSC Sureshot Mains Test Series
₹19000
Enroll Now
Prelims Powerup Test Series
Prelims Powerup Test Series
₹8500
Enroll Now
Enquire Now