Explanation:

Ozone depletion refers to the phenomenon of reductions in the amount of ozone in the stratosphere. The problem of ozone depletion is caused by high levels of chlorine and bromine compounds in the stratosphere. The origins of these compounds are chlorofluorocarbons (CFC), used as cooling substances in air conditioners and refrigerators, or as aerosol propellants, and bromofluoro carbons ( halons ), used in fire extinguishers. As a result of depletion of the ozone layer, more ultraviolet (UV) radiation comes to Earth and causes damage to living organisms. UV radiation seems responsible for skin cancer in humans; it also lowers production of phytoplankton and thus affects other aquatic organisms. It can also influence the growth of terrestrial plants. A reduction of approximately 5 per cent in the ozone layer was detected from1979 to 1990. Since the ozone layer prevents most harmful wavelengths of ultraviolet light from passing through the Earth’s atmosphere, observed and projected decreases in ozone have generated worldwide concern. This led to the adoption of the Montreal Protocol banning the use of chlorofluorocarbon(CFC) compounds, as well as other ozone depleting chemicals such as carbon tetrachloride, trichloroethane (also known as methyl chloroform), and bromine ,compounds known as halons . Ozone in lower atmosphere can cause chocking and photochemical smog. In large quantities it can prove to be fatal. · Because of the formation of polar vortex at poles and long winters, the ozone holes are only found at poles and not on lower latitudes