India has detected a new “double mutant variant” of the novel coronavirus, the health ministry said, adding to concern as the government struggles with the highest single-day tally of new infections and deaths this year.

Genome sequencing and analysis of samples from Maharashtra state found mutations in the virus that do not match previously catalogued “variants of concern” (VOC), the ministry said in a statement. Maharashtra is one of India's worst-affected states but the ministry said it was not clear if the new variant was causing an upsurge there or in other states.

Meanwhile, India reported 47,262 new infections over the previous 24-hour period, the highest since early November, taking its overall tally to 11.7 million. Only the United States and Brazil have higher caseloads.

The number of deaths from Covid-19 in India in the previous 24 hours rose to 275, the most this year, taking the total to 160,441, government data showed.