2. POLLUTION is the introduction by man into the environment of contaminants that contains harmful substances
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4. AIR POLLUTION Air pollution is the modification of the natural characteristics of the atmosphere by a chemical , particulate matter , or biological agent . The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth . Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems .
6. WATER POLLUTION Water pollution is a large set of adverse effects upon water bodies such as lakes, rivers, oceans, and groundwater caused by human activities.