<P> Water pollution is a major environmental issue in India . The largest source of water pollution in India is untreated sewage . Other sources of pollution include agricultural runoff and unregulated small scale industry . Most rivers, lakes and surface water in India are polluted . </P> <P> A 2007 study found that discharge of untreated sewage is the single most important source of pollution of surface and ground water in India . There is a large gap between generation and treatment of domestic waste water in India . The problem is not only that India lacks sufficient treatment capacity but also that the sewage treatment plants that exist do not operate and are not maintained . </P>

What is the main cause of water pollution in india