Water quality in the Ganges did not improve and rather deteriorated in many stretches, possibly even due to the discharge of untreated or partially treated sewage despite restrictions on human activities during the 68-day lockdown imposed since the March 25 to control Covid-19. pandemic, according to a report by the Central Pollution Control Board (CPCB) published on Wednesday. However, seven of India’s 19 major rivers, including the Brahmani, saw an improvement in water quality in April compared to the period before the closure, it added.
Ganges compliance with primary water quality decreased from 64.6% to 46.2% during closure. The report suggests that this may also be due to negligible seasonal flow, increasing pollution concentration, and no freshwater discharges upstream. Compliance was also down in Beas, Chambal, Sutlej and Swarnarekha.
The Baitarani, Mahanadi, Narmada and Pennar all met the quality criteria for outdoor bathing waters.
The CPCB sought to evaluate the trends of percentage variation (increasing or decreasing) in water quality only for parameters of bathing criteria such as pH, DO (dissolved oxygen), BOD (biological oxygen demand) and FC (fecal coliforms excluding fecal streptococci ). These are all measurements that show whether a river can sustain life and whether bathing is safe.
For the Ganges, during pre-closure, 42 of 65 monitored locations (64.6%) and during closure, 25 of 54 monitored locations (46.3%) were within desirable limits of the primary quality criteria outdoor water. bathrooms.
The Brahmani River’s compliance with primary water quality criteria for outdoor bathing improved from 85% in the pre-closure period to 100%. For Brahmaputra, it improved from 87.5% to 100% and for Cauvery from 90.5% to 96.97%. In the case of the Godavari it rose from 65.8% to 78.4%, Krishna 84.6% to 94.4%, Tapi 77.8% to 87.5% and Yamuna 42.8% to 66.67%.
Manoj Mishra, coordinator of the Yamuna Jiye Abhiyan, said that the closure occurred during the lean season of all rivers, particularly those originating in the Himalayan region. “The river flow contributes to the dilution of pollutants. So your analysis of the Ganges and other Himalayan rivers is correct. ”
Mishra said the rivers, including the Narmada, Pennar and Mahanadi, still have a low load of industrial effluents. “So it comes as no surprise that they met the bathing water quality standards before and during the shutdown.”
Mishra said CPCB should not have compared apples to oranges because the problems these rivers face are very different. “The clear impact of the closure was seen in the Yamuna downstream from Wazirabad because it has a high industrial effluent load that became zero during the closure and in March and April … there was rain in the Yamuna basin that caused greater discharges of Water”.
The 2,525 kilometer long Ganges originates in the northernmost part of Uttarakhand, flowing through Uttar Pradesh, Bihar, Jharkhand and West Bengal before discharging into the Bay of Bengal.
The report said that the lockdown period offered a unique situation to carry out water quality assessment of surface water bodies, including major rivers. It provided an opportunity to re-understand and redesign existing frameworks and put robust mechanisms in place to clean up identified contaminated river reaches, he added.
CPCB scientists said there could be different reasons behind the improvement in water quality in Yamuna during the closure and the worsening of the condition around the same period in many stretches of the Ganges.
“We found that the water in the Ganges had improved in Uttarakhand and some sections of UP during the closure. However, no improvement was observed in West Bengal and downstream Bihar. This, combined with poor flow, led to fewer places seeing an improvement in river water quality. Wastewater may have a greater contribution to pollution in these sections. While in Yamuna the contribution of industrial effluents, which was nil during the closure, appears to be moderate. Yamuna in Delhi received fresh water from the upper reaches during the closure. There were rains in the catchment areas of the river in the upper reaches in March, according to our analysis, “said a scientist from the CPCB, who participated in the study, on condition of anonymity.
CPCB separately observed its 46th Foundation Day on Wednesday and announced its plans for the next decade through 2030 to provide technical leadership for “science-based environmental management” and guide policy decisions to the government.
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