https://www.sciencedaily.com/releases/2021/10/211014142036.htm

SARS-CoV-2 had spread widely throughout India in the first wave, with initial results from the Indian Council of Medical Research finding one in five (21%) adults and one in four (25%) 10 to 17 year old adolescents had been infected. The figures were much higher in Indian megacities: by February 2021, over a half (56%) of individuals in Delhi were thought to have been infected.

Since the first case of COVID-19 was detected in Delhi in March 2020, the city had experienced multiple outbreaks, in June, September and November 2020. After reaching a high of almost 9,000 cases daily in November 2020, new cases steadily declined, with very few new infections between December 2020 and March 2021.