Almost 30% of the population in India's capital of New Delhi likely have been infected by the novel coronavirus, according to a serological survey of 15,000 people conducted by the local government, a figure that indicates infection numbers are much higher than those recorded.

The survey, which tested a sample of the population for the presence of antibodies, was done in the national capital territory in the first week of August, its health minister Satyendra Jain told a news conference on Thursday.

"We found that 29.1% of the population of Delhi had antibodies, which means that they were infected and have been cured," Jain said.

Delhi has a population of 20 million and has recorded a total of 140,767 cases of COVID-19, out of India's total of 2.84 million.

The findings of the survey are in line with what other cities like Mumbai and Pune have discovered, that a significant number of their people have been infected.

India reported a record daily jump of 69,652 coronavirus infections on Thursday, data from the federal health ministry showed. Deaths rose by 977 to a total of 53,866.

India is the worst-hit country in Asia and globally third only behind the United States and Brazil in number of cases.