The river water quality index (RWQI) of the upper Ganga canal has been computed to assess the effect of lockdown and unlock phases lead down by COVID-19 in India. Geospatial distribution of RWQI from January 2019 to December 2021 in the study area revealed significant impacts of lockdown on water quality. However, unlock phases (post lockdown) have deteriorated water quality since August 2020 and reached to actual conditions of the river by August 2021. To evaluate the lockdown as a management strategy to clean the river, other factors were reviewed including rainfall data, migration, and other activities. The results revealed that all the monitoring stations have improved water quality index ranging from 3 to 45 between March to June 2020. The River Ganga at Haridwar showed a two-fold improvement in the water quality index making it the highest positive impact of the lockdown, and at Rishikesh, the water quality index showed the least changes. The average decrease in RWQI has been observed to be 13 units in the year 2020 as compared to 2019 between March to June. In October 2020, RWQI has been observed to be higher as compared to the years 2019 and 2021. This is possibly due to a shift in rainfall patterns and other factors such as evapotranspiration, precipitation, and atmospheric temperature involved in river water quality control. Up to 60% reduction in average total coliforms and fecal coliforms has been observed due to the nationwide lockdown and a shift in human behavior towards cleaner and sustainable approaches.

The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro‐Fenton, and photo‐Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health.