Which one of the following is mainly responsible for the depletion of the ozone layer?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Chlorofluorocarbons
Chlorofluorocarbons are the freons. In the stratosphere they start radical chain reactions that upset the natural ozone balance, which depletes the ozone layer.
NCERT (2026-27 edition):
6.8.5 Freons – “The chlorofluorocarbon compounds of methane and ethane are collectively known as freons. … Most freon, even that used in refrigeration, eventually makes its way into the atmosphere where it diffuses unchanged into the stratosphere. In stratosphere, freon is able to initiate radical chain reactions that can upset the natural ozone balance.”