This report by the Central Water Commission (CWC) attempts to provide the water quality scenario of our rivers and evolve a methodology for identifying hot spots in Indian rivers. The water quality data is based on the average values observed during the last ten years (2001-2011) at 371 monitoring stations of CWC on almost all major, medium and minor rivers in India. In respect of Dissolved Oxygen and Biochemical Oxygen Demand, the Central Pollution Control Board's classification has been considered for evaluating the hot spot in the rivers.
The physical and chemical quality of river water is important in deciding its suitability for drinking purposes. As such the suitability of river water for potable uses with regard to its chemical quality has to be deciphered and defined on the basis of the some vital characteristics of the water. Bureau of Indian Standards (BIS) vide its document IS: 10500:1991, edition 2.2 (2003‐09) has recommended the quality standards for drinking water and these have been used for finding the suitability of river water. On this basis of classification, the natural river water of India has been categorized as desirable, permissible and unfit for human consumption.
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This report by the 
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