Main causes of water pollution are:
Chemical waste, industrial waste and agricultural processes.
Thermal waste from nuclear and thermal power plants.
Sewage and garbage.
Prevention of water pollution:
Domestic sewage should be treated before being discharged into rivers.
Using of non-biodegradable substances like detergents should be stopped.
Trees and plants must be planted along the banks of rivers.
Puri cation of water bodies should be carried out.
The waste products of industries should be treated before they are discharged into rivers.