NEW DELHI: Strongly rebutting claims of a substantial increase in level of pollutants in Ganga in a report by Varanasi-based Sankat Mochan Foundation, the National Mission for Clean Ganga said such high levels of biochemical oxygen demand (BOD) have never been reported for the river.
Questioning the capacity of the Foundation to carry out such tests, the NMCG - a central agency which has been implementing the government's ambitious Ganga rejuvenation programme - said the high level of BOD claimed were not "scientific at all" as such a scenario could lead to sudden depletion of Dissolved Oxygen (DO) level severely impacting aquatic life. Only the Central Pollution Control Board had the wherewithal to monitor pollution along the length of the river.
Referring to CPCB data of the last six years, the Mission said the DO level has, in fact, been found to be within "acceptable limits" of notified primary water quality criteria for bathing. The BOD level should be less than 3 mg/L, DO should be 5 mg/L or more and desirable faecal coliform should be 500 MPN (most probable number)/100 ml with maximum permissible level being 2,500 MPN/100ml.
The Foundation has gone by data collected by its laboratory at Tulsi Ghat in Varanasi and claimed that the BOD level has increased from 46.8-54 mg/L to 66-78 mg/L during January 2016 to February 2019. Similarly, the NGO claimed faecal coliform in the river at Varanasi have increased from 4.5 lakh (upstream at Nagwa) and 5.2 crore (downstream at Varuna) in January, 2016 to 3.8 crore (upstream) and 14.4 crore (downstream) in February, 2019. Calling these claims "incorrect", the NMCG flagged the scientific data of the CPCB which carried out continuous water quality monitoring at two locations in Varanasi.
It said, "Analysis of water quality monitoring data of CPCB for these two stations located on main stem of Ganga in Varanasi for the month of January for period 2016-19 indicates that minimum value of DO varied between 6.7 to 7.6 mg/L and indicated healthy state of river."