Chlorofluorocarbons, which are widely used in refrigerators, fire extinguishers and aerosol sprayers, are released into the air and react with the ozone present in the ozone layer and destroy it gradually. This causes the depletion of the ozone layer. If the ozone layer becomes thinner, harmful ultraviolet radiations will enter the earth and may cause skin cancer and other ailments in humans and also affect plants and animals.