Extrapolated, the antibody test on 15,000 residents means that another 5.8 million people in the bustling capital may have caught the virus, more than 37 times the official total of 156,139 infections.
India is already officially the third most affected country after the United States and Brazil, and the Ministry of Health on Wednesday reported a record increase of 69,652 new infections, bringing the total to 2.84 million.
On Thursday, Delhi’s fitness minister Satyendra Jain said blood tests on 15,000 citizens before this month that 29.1% of them had anti-virus antibodies.
However, scientists say antibody tests should be treated with caution, as they are also run into other coronaviruses, not just newer COVID-19.
A survey conducted between June and July found that 23% of those examined had been exposed to the virus in the city.
Surveys in other cities in India have also revealed more infections than official figures suggest.
In the western city of Pune, 51.5% of respondents in five severely affected wallets had antibodies in their blood, according to a recent survey.
Another, last July, revealed that 57% of the other people examined in Mumbai’s slums were inflamed, more than official knowledge suggests.
“These studies are useful and necessary, but their interpretation is important,” said Rajib Dasgupta, who runs the Center for Social Medicine and Community Health at Jawaharlal Nehru University in Delhi.
“This cannot be implemented throughout the city,” he said, noting that Pune’s examination was conducted in a densely populated domain of the city.