Problem of water pollution is assuming dangerous dimensions.
Harmful chemicals of chemical, textile, sugar, metal, medicine, and fertilizer industries are being disposed off in rivers.
Water pollution is caused mainly by the following sources:
(1) Industrial effluents
(2) Domestic effluents
(4) Agricultural effluents
(5) Oil pollution
(6) Thermal pollution
(7) Social sources
(8) Radioactive disposal.
Natural form of water has deteriorated due to various natural and human sources. Some pollutants enter into water, causing great harm to the environment. The main among them are mercury, lead, zinc, fluoride, sodium, phenol, nitride and armenizm.
Water pollution in India has increased to a great extent. According to the estimate by researchers of National Environmental Engineering Research Institute (NEERI), Nagpur, about 70 per cent groundwater in the country has become unfit for human consumption.
According to scientists, there is satisfactory sewerage arrangement only in eight out of 142 big cities, partial sewerage system in 52 cities and in remaining 82 cities there is no sewerage, resulting in absence of disposal of waste and leading to water pollution.
Various sacred rivers of India are losing their quality of water 37 per cent population of India lives in the drainage basin of river Ganga and 47 big cities and 66 small towns located on its sides, are polluting its water. Apart from rivers of India, lakes and other important water reservoirs are also becoming polluted.