Although it is difficult to say how many of these deaths have been caused by Covid-19, they are a measure of the overall impact of the pandemic.
Researchers from the US-based Center for Global Development used three different data sources to estimate India's excess all-cause mortality during the pandemic until 21 June.
They extrapolated death registrations from seven states, accounting for half of India's population. India conducts yearly mortality surveys but has only published numbers up to 2019.
Second, the researchers applied international estimates of age-specific infection fatality rates - the number of people that die from the virus - to data from two countrywide antibody tests, also called sero surveys.
Third, they looked at India's consumer survey of 868,000 individuals across 177,000 households which also records whether any member of the family had died in the past four months.
Taken together, the researchers found that excess deaths were estimated to be in the range of 3.4 million to 4.7 million - about 10 times higher than India's official Covid-19 death toll.