India's official death toll from COVID-19 has reached the grim milestone of 400,000, although experts say the actual number of dead could be one million or even higher.
India added 100,000 deaths in 39 days, a Reuters tally showed, as a brutal second wave of infections swept across cities and into the vast countryside where millions remain vulnerable without access to vaccines.
Overnight, the country recorded 853 deaths, taking the toll past the 400,000 mark, health ministry data showed.
India's official death toll is the third-highest globally.
"Undercounting of deaths is something that has happened across states, mostly because of lags in the system, so that means we will never have a true idea of how many people we lost in this second wave," Rijo M John, a professor at the Rajagiri College of Social Sciences in the southern city of Kochi, said.
While still elevated, the number of new infections has eased to two-month lows since hitting a peak of 400,000 a day in May.
The government has shifted its focus to mass immunisations amid warnings from disease experts of a looming third wave as the country slowly re-opens and a new variant, locally called the Delta Plus, emerges.
Prime Minister Narendra Modi's government last week began a nationwide campaign to inoculate all of the country's adults, and aims to reach 950 million people by the end of the year.
But after a fast start the pace of vaccinations has floundered, official data shows.
India administered an average of 3.5 million doses a day this week, as against 6.6 million doses last week.
Experts have attributed the peak of nine million doses on June 21 to states stockpiling for a burst of inoculations to fire up Modi's campaign.
Just six per cent of all eligible adults in the country were inoculated with the two mandatory doses, official data from the government's Co-Win portal showed.
In India's financial capital of Mumbai, vaccination centres were only open for three hours on Friday and the number of doses available was limited, the city's civic body said.
India has recorded 30.45 million cases of COVID-19 since the outbreak of the pandemic last year, and is the second-most affected country behind the United States, which has 33 million cases.
The United States has more than 604,000 deaths, while about 518,000 people have died in Brazil.