Ozone depletion is the gradual thinning of Earth’s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities.

When chlorine, bromine and other ODS (Ozone Depleting Substance) atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.

Ozone Depleting Substances are substances which cause the depletion of the ozone layer. It includes :- chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrobromoflurocarbons (HBFCs), halons, methyl bromide, carbon tetrachloride, methyl chloroform.

Some compounds release chlorine and bromine on exposure to high ultraviolet light, which then contributes to ozone layer depletion. Such compounds are known as Ozone Depleting Substances (ODS). Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons—gases formerly found in aerosol spray cans and refrigerants—are released into the atmosphere.

Some steps / measures we can take :- Buy air-conditioning and refrigeration equipment that do not use HCFCs as refrigerant. Buy aerosol products that do not use HCFCs or CFCs as propellants. Conduct regular inspection and maintenance of air-conditioning and refrigeration appliances to prevent and minimize refrigerant leakage.

The Montreal Protocol, finalized in 1987, is a global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS).