Rivers get polluted in the following ways:
(i) River water is used for domestic, municipal, industrial and agricultural purposes. This affects the quality of water. The volume of river is also reduced because more and more water is being drained out of them.
(ii) 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-cleansing capacity of the river.
(iii) The increasing urbanization and industrialization also contribute to the river pollution. Due to these reasons the pollution level of many rivers has been rising.