The ozone hole occurs during the Antarctic Spring, which happens from September to early December, as strong westerly winds circulate around the continent. Within this polar vortex, about 50% of lower atmospheric ozone is destroyed during this time.

The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam- blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS).

For more relevant articles refer to the links given below:

• UPSC Environment and Ecology Questions
• Environment & Ecology Trend Analysis: UPSC Strategy
• UPSC Environment and Ecology