The Lock Down imposed in the country on March 22, 2020 has improved air quality and water quality. According to CPCB (Central Pollution Control Board), 40 million litres of waste water enters water bodies.
The water pollution of a river is measured based on Biological Oxygen Demand (BOD). The Ganga has become dump yard for industrial waste and untreated sewage. Since 1985, several schemes and programmes have been launched to clean Ganga starting with Ganga Action Plan I. Later in 2015, the biggest initiative Namami Gange was launched.
After lock down, the real time monitoring data from the CPCB say that out of 36 monitoring points of the Ganges, 27 are now clean and suitable for wildlife and fisheries propagation. The dissolved Oxygen values have reported to have improved in the cities like Varanasi where the pollution peaked. The improvement has been from 6.8 mg/litre as compared to 3.8 mg/litre before lock down.
The major reasons for the improvement in the water quality is that activities such as bathing, tourism, fairs near the ghats were stopped. Also,the major industrial activities around the river were stopped. Though sewage persists to enter the river, now the situation is different. This is because when sewage effluents get mixed with the industrial effluents, it is highly difficult for the river to assimilate itself.