The epidemic of Novel COVID-19 was reported in India in January 2020 and increased day by day due to the movement of people from abroad to India and then to the different parts of the country. The COVID-19 has been declared as pandemic because of its high transmission rate and coved more than 2010 countries of the world. Under this scenario when there is no medicine for its treatment, the only solution to this problem is to break the chain of transmission and restrict the count of infected people. To contain a coronavirus (COVID-19) outbreak, the Government of India announced the nationwide lockdown with effect from the midnight of 24th March 2020 followed by the extension of the lockdown periods and presently it is in its 4th phase. The various provisions were made under lockdown for closing the industries, transportation, etc. except the essential services. It has been very interesting to note that the behavioural changes in nature are highly positive and atmosphere, hydrosphere, and biosphere are rejuvenating and it gives an appearance that the earth is under lockdown for its repairing work. Under this natural recovery, we tried to look at the improvement in the water quality of the Yamuna River in Delhi, which has been one of the burst polluted rivers. To study this river, the concentrations of pH, EC, DO, BOD, and COD have been measured which showed a reduction by 1-10%, 33-66%, 51%, 45-90%, and 33-82% respectively during the lockdown phase in comparison to the pre-lockdown phase. The Nizamuddin Bridge, Okhla U/s, Najafgarh Drain and Shahdara Drain were the major hotspots responsible for the deterioration of the water quality of Yamuna River while passing by Delhi region. Five major locations of Yamuna River have been analysed in this paper that showed a very impressive recovery of the water quality during the lockdown phase as compared to the pre-lockdown status of water quality.