NEW DELHI: The Gangas water quality may not be as per desired standards along its entire course of 2,525 km but the holy river is not the dirtiest as none of its five polluted stretches falls in the list of top 25 dirtiest patches of 351 polluted river stretches noted by government studies.
Analysis of Central Pollution Control Board (CPCB) data shows that the 10 dirtiest river stretches in 2018 were found on river Vasishta (Tamil Nadu), Ghaggar (Haryana and Punjab), Bhadra (Gujarat), Mithi (Maharashtra), Sabarmati (Gujarat), Hindon (Uttar Pradesh) and Sutlej (Punjab), among others.
These polluted stretches were identified on the basis of their very high Biochemical Oxygen Demand (BOD) level — a key indicator of organic pollution which affects dissolved oxygen (DO) level that impacts aquatic life. The highly polluted stretches have virtually no oxygen which means no life can exist.
Data from the past three CPCB reports, carrying water pollution monitoring figures on different stretches during 2002-17, shows that the number of polluted river stretches in the country increased from 121 in 2009 to 302 in 2015 and further to 351 in 2018 with more rivers coming into the monitoring regime in the past 15 years. The bulk of the increase, however, was noticed in the least polluted category in the list
As far as Ganga is concerned, only one of its five polluted stretches is in the critical category where the BOD level is more than 30 mg/l. This stretch was found where Varuna river, a minor tributary, meets Ganga in Varanasi. The other polluted stretches include Haridwar-Sultanpur, Kannauj-Kanpur (UP), Buxar-Bhagalpur (Bihar) and Tribeni-Diamond Harbour (West Bengal).
The increase in a number of polluted river stretches can be attributed to discharge of untreated industrial and municipal waste into rivers over the years. Data shows that over 60% of sewage generated in urban areas across the country finds its way into rivers without any treatment.
The country has the capacity to treat only 23,277 million litres per day (MLD) of sewage against the generation of 61,948 MLD of sewage, leading to pollution in one or the other river in all states except Arunachal Pradesh.
Other north-eastern states, however, are not that lucky. Along with Assam, which figured at the second spot after Maharashtra in terms of a high number of polluted river stretches in 2015 and 2018, the entire Read More – Source
