The Union Health Secretary bluntly told the 28 federal states on Tuesday to get a grip on lax coronavirus prevention measures "right now" to prevent healthcare systems being overwhelmed by a surge in infections.
India's current caseload of 12.1 million ranks third behind only the United States and Brazil, with testing unable to keep up with demand. The daily rise in cases has quadrupled in the space of a month.
"The current rise in cases ... has the potential of overwhelming healthcare systems unless checked right now," Health Secretary Rajesh Bhushan said in a letter to the states.
"Many districts in the country are seeing clusters of cases emerging because of specific events and/or places where crowding happens, or where a large number of people are in close contact coupled with a lack of a COVID-appropriate behaviour."
On Tuesday, India recorded 56,211 new cases, a slight dip after a reduction in testing over a long weekend.
Mr Bhushan asked states to enforce mask-wearing and physical distancing, and to increase testing, tracing and quarantining, or else face "heavy costs".
About 800,000 tests were carried out on Monday, compared with more than 1 million at the peak of India's outbreak in September.
Despite the warnings, top politicians including Prime Minister Narendra Modi himself have been addressing rallies and meetings of tens of thousands of people, sitting or standing shoulder-to-shoulder, with only a handful wearing masks.
Multi-phase elections in four big states began last week and will run through next month.
Vinod Kumar Paul, a senior government health official, told a news conference the situation across India was going "from bad to worse".
India's richest state, Maharashtra, accounted for more than 31,000 of the total new cases reported in the latest 24 hours. Deaths rose by 271 nationwide, to 162,114.
Maharashtra is considering imposing stricter curbs from Thursday, but opposition parties and industrialists have opposed a lockdown, saying it hurts the poor the most.
India has accelerated its nationwide immunisation campaign, simplifying the process, opening more vaccination centres and restricting exports after criticism that more of its production was going abroad than to India's own population.
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