Ganges River water quality was assessed to record the changes due to the nation-wide pandemic lockdown. Satellite-based (Sentinel-2) water quality analysis before and during lockdown was performed for seven selected locations spread across the entire stretch of the Ganges (Rishikesh–Dimond Harbour). Results revealed that due to the lockdown, the water quality of the Ganges improved with reference to specific water quality parameters, but the improvements were region specific. Along the entire stretch of Ganges, only the Haridwar site showed improvement to an extent of being potable as per the threshold set by the Central Pollution Control Board, New Delhi, India. A 55% decline in turbidity at that site during the lockdown was attributed to the abrupt halt in pilgrimage activities. Absorption by chromophoric dissolved organic matter which is an indicator of organic pollution declined all along the Ganges stretch with a maximum decline at the downstream location of Diamond Harbour. Restricted discharge of industrial effluent, urban pollution, sewage from hotels, lodges, and spiritual dwellings along the Ganges are some of the reasons behind such declines. No significant change in the geographic trend of chlorophyll-a was observed. The findings of this study highlight the importance of regular monitoring of the changes in the Ganges water quality using Sentinel-2 data to further isolate the anthropogenic impact, as India continues the phase-wise opening amidst the pandemic.

Several factors affect microorganism survival and distribution in the aquatic environment including humans and animal populations. Present study assessed the influence of physicochemical factors on the distribution of presumptive coliform along the stretch of River Ganga in West Bengal, India. Nevertheless, Ganga water is polluted by drainage waste released from various urban and rural regions, agricultural and domestic wastes, industrial effluents and human activities. Drains discharge major portions of domestic wastes and untreated sewages, into the aquatic environment. Physico-Chemical factors affecting the survival of fecal microorganisms in the River Ganga as per the study included parameters like pH, conductivity, alkalinity, biochemical oxygen demand (BOD), chemical oxygen demand (COD) etc. In Ganga some parameters were seen to vary dramatically along the stretch. All the stations had the total coliform counts of more than 500 and Tribeni being the upstream station had lower value for coliforms. Ganga Sagar was found to have the least count for coliforms because of high salinity.

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