Question raised in Lok Sabha on Chemical Contamination of Rivers, 09/03/2018. There are 38 rivers, 27 lakes, 3 ponds and 18 tanks which are critically polluted having a COD concentration of more than 250 mg/l, which is the discharge standard for a polluting source such as sewage treatment plants and industrial effluent treatment plants. The State-wise list of these polluted rivers, lakes, ponds and tanks are given in Annexure.