<P> The levels of BOD are severe near the cities and major towns . In rural parts of India, the river BOD levels were sufficient to support aquatic life . </P> <P> Rivers Yamuna, Ganga, Gomti, Ghaghara River, Chambal, Mahi, Vardha are amongst the other most coliform polluted water bodies in India . For context, coliform must be below 104 MPN / 100 ml, preferably absent from water for it to be considered safe for general human use, and for irrigation where coliform may cause disease outbreak from contaminated - water in agriculture . </P> <P> In 2006, 47 percent of water quality monitoring reported coliform concentrationst above 500 MPN / 100 ml . During 2008, 33 percent of all water quality monitoring stations reported a total coliform levels exceeding those levels, suggesting recent effort to add pollution control infrastructure and upgrade treatment plants in India, may be reversing the water pollution trend . </P> <P> Treatment of domestic sewage and subsequent utilization of treated sewage for irrigation can prevent pollution of water bodies, reduce the demand for fresh water in the irrigation sector and become a resource for irrigation . Since 2005, Indian wastewater treatment plant market has been growing annually at the rate of 10 to 12 percent . The United States is the largest supplier of treatment equipment and supplies to India, with 40 percent market share of new installation . At this rate of expansion, and assuming the government of India continues on its path of reform, major investments in sewage treatment plants and electricity infrastructure development, India will nearly triple its water treatment capacity by 2015, and treatment capacity supply will match India's daily sewage water treatment requirements by about 2020 . </P>

Which is the largest source of water pollution in major rivers of india