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Topic Ozone depletion
Asked 9 times across 4 UPSC exams over 46 years (1979–2025), peaking in 2024.
Key insights
- Most tested in GEO — 4 of 9 PYQs
- Most asked in 2024
- Recurs across 7 years (1979–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1979 → CAPF 2015 → GEO 2021 → CDS 2024
How the concept evolved
Rising — more than half its appearances (5 of 9) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
GEO2025
Which one of the following Protocols was signed in the year 1987 to reduce the production and use of ozone-depleting substances?
- A Kyoto Protocol
- B Montreal Protocol ✓
- C Nagoya Protocol
- D Cartagena Protocol
✓ Correct answer: (B)
Environment & Ecology › International Environmental Agreements
CDS2024
Ozone hole is a region over :
- A the Antarctic caused mainly by CFC gases. ✓
- B the Antarctic caused mainly by carbon dioxide gas.
- C the Arctic caused mainly by CFC gases.
- D the Arctic caused mainly by carbon dioxide gas.
✓ Correct answer: (A)
Environment & Ecology › Pollution & Waste
GEO2024
Consider the following statements about Chlorofluorocarbons (CFCs)
- CFCs remain inert in the troposphere but slowly diffuse into the stratosphere
- CFCs in the upper atmosphere are subjected to UV radiations, generating free radical chlorine that immediately reacts with O3 to form a radical called chlorine monoxide (ClO)
- Each ClO can initiate a series of chemical reactions, leading to the destruction of the ozone layer
How many of the statements given above is/are correct ?
- A 1
- B 2
- C 3 ✓
- D None
✓ Correct answer: (C)
Environment & Ecology › Pollution & Waste
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