NEW DELHI - India continued to set daily record rises in coronavirus cases as official mortality rates stayed suppressed.

The country saw an increase of 96,551 new cases in the last 24 hours, according to the Ministry of Health and Family Welfare on Friday (Sept 11).

With new daily caseloads far surpassing other countries', these figures come even as a sero-prevalence survey by the Indian Council of Medical Research (ICMR) found that India had an estimated 6.4 million infections in May, when official figures for the middle of that month put the number of positive cases at 85,940. This means that potentially millions went undetected.

At the time, the country was averaging 100,000 tests a day, which has now been ramped up to one million tests a day on average.

For the sero-prevalence survey, which tracks antibodies to assess exposure to the virus, 28,000 people were tested.

Experts said India's numbers would continue going up, likely surpassing the US, which currently has the highest number of cases. India now has 4.56 million cases. The US has 6.59 million cases.

"It will keep going up. Virus transmission is taking place more or less freely. There is no great mystery about it... We have a large population," said leading Indian epidemiologist Jayaprakash Muliyil.

"Fortunately, the future is not bleak... People who get the disease and get out of it seem to have good immunity."

India implemented a complete lockdown on March 25, which brought all economic activity to a halt. It has since gradually loosened restrictions as worries have grown about the health of the economy.

Still, the government has taken India's low mortality rate and high recovery rate (77.65 per cent) as a good sign and a result of efforts to improve medical infrastructure and hasten detection of cases.

India's mortality rate, at 1.7 per cent as calculated by Johns Hopkins University of Medicine, is among the lowest. The death rate in Mexico, the highest worldwide, stands at 10.7 per cent. The US, which has the world's highest caseload, has a death rate of 3 per cent.

Experts believe India's low mortality rate could be due to a combination of factors, including a younger demographic, with 65 per cent below the age of 35, as well as the elderly staying at home instead of in old age homes like in the West.

But another key factor is seen to be the potential under-reporting of cases.

The death toll as of Friday was 76,271.

Due to co-morbidities in patients, cases are also reportedly being written off as non-Covid. Several states like Assam have been faced criticism of under-reporting cases.

"Covid-19 cannot be eliminated as a cause of death (in cases) even if there are co-morbidities," said Dr Rajib Dasgupta, chairman of the Centre of Social Medicine and Community Health at Jawaharlal Nehru University. He noted that many states are reviewing and verifying Covid deaths.

With over 940,000 active cases and spiking infections, India's health infrastructure will now face its biggest test.

As numbers rise, Kerala Health Minister K. K. Shailaja, according to a government press release, has warned that the Covid-19 death toll in the state may go up further due to lifting of restrictions.

The federal health ministry on Thursday asked states not to put restrictions on the cross border movement of oxygen.

"Now some states are showing signs of strain on health services. I believe mortality issues will come into much more focus," said Dr Muliyil.