air pollution comes from factories, power stations and cars. chemicals in the smoke from power stations cause a lot of damage. they can travel hundreds of miles in the wind before falling to the ground in the rain. but this "chemical rain" gradually destroys trees in the forests and kills fish in the lakes. in germany, over 50% of the country＇s trees had been damaged by the year 1986.

　　time and time again there are serious accidents that pollute the air. in 1986 there was a bad accident at a nuclear power station in russia. a cloud of radiation crossed the whole of europe. it is said that 125,000 people died in russia as a result of illnesses caused by this accident.

　　in 1984 there was a serious accident at a factory in india and a cloud of dangerous gas covered the town of bhopal. over 2,500 people were killed that night, and hundreds of thousands of people were injured. many of the injured lost their sight.