India’s Covid-19 deaths may be six times the Union health ministry’s official count or even higher, researchers said on Sunday after analysing the central government’s own civil registration and health information datasets.

Their study, based on three independent data sources, has estimated 2.7 million to 3.4 million deaths through the country’s two waves until July 2021. Even the lower estimate is about 6.4 times the 421,000 deaths officially recorded until Sunday.

“We used three distinct datasets reaching similar conclusions,” Prabhat Jha, professor and epidemiologist at the Centre for Global Health Research, University of Toronto, Canada, who led the study, told The Telegraph.

The findings place India’s Covid-19 death rate at about 2,000 per million population, close to the range reported in Latin America, according to the study by Jha and his colleagues that has been posted on MedRxiv, an online preprint server, but not been peer reviewed yet.

India’s health ministry has for months used official death counts to suggest that India’s Covid-19 death rate is among the lowest measured per million population — currently about 309 per million.

The new study is the latest among independent research efforts that have used different methodologies to estimate the excess deaths (compared with corresponding periods in previous years after correcting for population rise) or Covid-19 deaths in India, all indicating that the country has vastly undercounted its deaths.

The health ministry has described these efforts at extrapolating the excess Covid-19 deaths in India as “audacious” and said the country has a “robust system of recording Covid-19 deaths”.

The ministry has added that it has always asked the states to conduct death audits and record any missed deaths.

Many public health experts in India have argued since April that the crowds at the crematoriums and funeral sites in multiple cities, and the bodies dumped in rivers, reflected a large volume of excess deaths that were difficult to manage through the available crematorium or funeral infrastructure.

Jha and his collaborators used the Centre’s Civil Registration System (CRS) that records births and deaths, using data from eight states and seven cities, and the health ministry’s Health Management Information System (HMIS) that contains mortality data from around 200,000 health facilities across India.

They compared the data from the CRS and the HMIS for 2020 and 2021 with the death data between 2015 and 2019 to estimate the “excess mortality”, which would most likely have occurred because of Covid-19 during 2020 and 2021.

Across the two waves, the median excess mortality during 2020 and 2021 compared with earlier years, going by CRS data, was 32 per cent for the states and 37 per cent for the cities.

The HMIS data suggested 27 per cent excess mortality from July 2020 to May 2021, with 120 per cent excess mortality during April-May 2021.

The researchers also collaborated with India’s Centre for Voting Opinion and Trends in Election Research, or C-Voter, which questioned over 137,000 randomly selected households across India about Covid-19 deaths among their members.

The national survey by C-Voter found about 3.5 per cent adults reporting a Covid-19 death in their household during April-June 2021 and estimated 29 per cent to 32 per cent excess deaths between June 2020 and June 2021.

These proportions of excess deaths are consistent with the 32 per cent excess deaths from the CRS estimates and 27 per cent excess deaths from the health facilities covered by the HMIS, the researchers said.

The health ministry has said that excess mortality is a term used to describe an all-cause mortality figure, and that attributing these deaths to Covid-19 is “completely misleading”.

But many health experts say the spikes in deaths during the Covid-19 pandemic are likely to be caused by Covid-19.

Any changes in the death figures from causes apart from Covid-19 “are likely small compared to the sharp increases in Covid-19 deaths”, particularly during the second viral wave, Jha and his colleagues said in their study.

Earlier this year, Bhramar Mukherjee, a senior biostatistician at the University of Michigan, and her colleagues had estimated that around 1.2 million people had died of Covid-19 in India up to May 15 this year when the official count was about 270,000.

Last week, Arvind Subramanian, former chief economic adviser to the Indian government who is currently at Brown University in the US, and his colleagues had used different methodologies for three estimates of India’s excess deaths — 3.4 million, 4 million and 4.9 million.

The health ministry has said the extrapolation of deaths “has been done on an audacious assumption that the likelihood of any given infected person dying is the same across countries, dismissing the interplay of direct and indirect factors such as race, ethnicity, genomic constitution of a population and previous exposure levels to other diseases and associated immunity”.