1. The growing domestic and industrial demand for water from rivers naturally affects the quality of water. As a result more and more water is being drained out of the rivers reducing their volume.
2. A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This affects not only the quality of water but also the self cleaning capacity of rivers.
3. The increasing urbanisation and industrialization is also responsible for increasing pollution level of many rivers.