India said on Thursday it had curbed an increase in Covid-19 infections, with a fifth of its districts reporting no new cases for a week, even as its immunisation campaign has covered 2.4 million people.

The country of 1.35 billion has recorded the highest number of cases in the world after the United States, though the rate of infection has come down significantly since a mid-September peak. Some studies have suggested pockets of India have attained herd immunity through natural infection.

“India has successfully contained the pandemic,” Health Minister Harsh Vardhan said, noting that fewer than 12,000 cases were reported in the past 24 hours.

He said 146 of India’s 718 districts have had no new cases for a week and 18 districts for two weeks.

“India has flattened its Covid-19 graph,” Vardhan added.

With infections falling, the government said here that from February 1 it would lift curbs on the use of public swimming pools, allow cinema halls and theatres to seat more than 50 per cent of capacity and let all types of exhibition halls to operate.

The world’s second most populous country started its Covid-19 immunisation programme on January 16, with the aim to reach 300 million people by July-August.

India has so far reported 10.7 million infections and 153,847 deaths — one of the world’s lowest fatality rates from the disease, attributed partly to its younger population.

Thyrocare Technologies Ltd, one of India’s top-three diagnostic chains, told Reuters antibody tests it had done on more than 700,000 people showed that 55pc of the country’s population may have already been infected.

The World Health Organisation says at least 60pc to 70pc of the population needs to have immunity to break the chain of transmission.

A top Indian vaccine official told Reuters he did not think India had reached that level yet, but that even a smaller percentage could help slow the spread of the virus.

“Most of our highly populated districts and cities have had their run of the pandemic by now [...] and may have what you like to call herd immunity, to an extent,” Vinod Kumar Paul, who heads a committee on vaccine strategy, said earlier this month.