Question raised in Rajya Sabha on Action Plan for Pollution Free Rivers, 08/07/2019. The 351 river stretches on 323 rivers are prioritised based on BOD values in five classes. Polluted River Stretches of Priority 1 and 2 are located in 20 States and Union Territories, whereas polluted stretches of Priority 3, 4 and 5 are located in 28 States and Union Territories.