Ozone layer is very important for the existence of life on earth because it absorbs most of the harmful ultraviolet radiation coming from the Sun and prevents them from reaching the earth. The ultraviolet radiations have extremely harmful effects on human beings, other animals as well as plants. For example, ultraviolet rays can cause skin cancer. They also damage the eyes by causing an eye disease called cataract. Ultraviolet rays damage immune system by lowering the bodys resistance to diseases. Thus, ozone layer in upper atmosphere protect us from these diseases by absorbing ultraviolet rays coming from the sun. This decrease has been linked to synthetic chemicals like chlorofluorocarbons (CFCs) which are used as refrigerants and in fire extinguishers. In 1987, the United Nations Environment Programme (UNEP) succeeded in forging an agreement to freeze CFC production at 1986 levels. By developing substitutes to freeze CFCs; scientists have already developed some substitutes which are ozone friendly.
