Air pollution has existed ever since humans first started the use of fire for agriculture, heating and cooking. In modern times, principal air pollution sources are various industries like steel plants, chemical plants, petroleum refineries, fertilizer plants, rubber manufacturing plants, paper mills, power plants etc. These emit in the atmosphere large amounts of pollutants like dust, smog, toxic gases like sulphur dioxide and other varieties of corrosive vapours. Other sources of air pollutants are automobiles, space heating, refuse disposal etc.
Most pollutants are washed out of the air by rain and wind. Pollutants in the atmosphere mix with rain. These acid rains falls on forests and lakes, killing fish, plants and animals. There are large lifeless areas caused by acid rain in industrial areas such as Europe, USA and Canada. Acid rains not only affect human health but certain wonderful ancient buildings that are located in London, Athens and Rome. One of the the greatest affects of air pollution is Global warming, an increase in the world’s temperature due to the increase of carbon dioxide in the atmosphere. As a result of the global warming the sea level will be increased due to which some of the low- lying countries like Maldives would be under water