Question

Mention any three activities which are responsible for depletion of ozone layer

Answer 1

use CFC
burning of plastics
refrigerators

Answer 2

hope this answer helps you.
1. Use of Chlorofluorocarbon (CFC's) in refrigerators and air conditioners. These CFC depletes ozone by  reacting with the ozone and breaking it to oxygen.

2. Water vapours prevents formation of ozone. 

3. Compounds of bromine and bromine oxide

4. Compounds of chlorine like carbontetrachloride and methylchloroform