Q. With reference to ‘ozone layer’, which of the following statements is/are correct?
1. Ozone layer shields the surface of the earth from the ultra-violet radiations from the sun.
2. Ozone depletion has been linked to the chlorofluorocarbons.
Select the correct answer from the code given below :
a) Only 2
b) Neither 1 nor 2
c) Both 1 and 2
d) Only 1
Correct Answer: c) Both 1 and 2
Question from UPPSC Prelims 2025
Explanation:
Statement 1 is correct: The stratospheric ozone layer (about 15–35 km altitude) absorbs virtually all UV‑C and most UV‑B radiation from the Sun, thereby shielding Earth’s surface and living organisms from harmful ultraviolet radiation.
Statement 2 is correct: Ozone depletion is linked to chlorofluorocarbons (CFCs). CFCs, once in the stratosphere, are photolyzed by UV light, releasing chlorine radicals that catalytically destroy ozone (e.g., Cl + O3 → ClO + O2), contributing to phenomena like the Antarctic ozone hole. This understanding underpins the Montreal Protocol restricting CFCs.
Therefore, both statements are correct.
