More on that study in India:
The blood tests were collected from just over 29,000 people in 21 states or territories between mid-August and mid-September.
The new figures are a sharp jump from the first sero-survey results, which the ICMR said showed that around 0.73 percent of adults in India - about six million people - were infected by May.
Scientists warn, however, that antibody tests should be treated with caution because they also pick up exposure to other coronaviruses, not just the one that causes Covid-19, the disease which has killed more than 1 million people worldwide since it emerged late last year.
India - which has one of the world’s most poorly funded healthcare systems - has gradually lifted a strict lockdown imposed in late March even as infections steadily climb, to revive its battered economy.