Ozone layer of upper atmosphere is being destroyed by:

Chlorofluorocarbons (CFCs) come in contact with atmospheric gases and eventually reach stratosphere where they cause depletion in ozone layer.CF2Cl2g →UV  C∙lg +  C∙F2 Clg;  C∙l + O3 →  Cl O∙ (g) + O2(g); Cl O∙ (g) →   C∙l (g) + O2(g)