The western state of Maharashtra, which has long been a virus hotspot, accounts for more than half the new infections.
India's caseload began to dip at the start of 2021, but poor adherence to Covid safety norms seems to be driving a fresh surge in several states.
India has so far recorded more than 11 million Covid cases and 158,000 deaths.
The caseload has been steadily climbing for weeks now. Seven other states - Kerala, Punjab, Karnataka, Gujarat, Tamil Nadu, Haryana and Madhya Pradesh - are also reporting a surge in infections.
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"I am not surprised," says Dr Srinath Reddy, president of the Public Health Foundation of India and an adviser to the federal and state governments on tackling Covid-19. "I was hoping it wouldn't happen but I can't say I am surprised."
He says the arrival of new coronavirus variants, which Indian scientists are already on the hunt for, "makes it even more complicated, but right now we don't have an estimate of how much that has influenced the current situation".
But the clearest reason for the uptick, he adds, is that "people are no longer observing public health precautions such as masking".
Indoor spaces such as offices, restaurants, wedding or conference venues and cinema halls have all reopened across India. So people have been gathering often in closed, air-conditioned spaces, without necessarily wearing masks.
Dr Reddy says all these are typical of urban life - and this is why the surge in cases is largely being reported from urban districts - Mumbai, Thane, Pune, Nagpur - and states that are heavily urbanised, such as Maharashtra and Kerala in the south.
Lack of masking and social distancing, and poor test and trace have all added to the spike in Maharashtra, Dr Sanjay Oak, a member of the state's Covid task force, told the BBC recently.
Part of the reason for the laxity, Dr Reddy believes, is the "flag of herd immunity" that India raised as caseloads dropped.
"The misconception that we have become immune is something we must dispel from the public mind," he says.
The latest spike comes early on in India's vaccination drive, which began in January. Nearly 30 million people have received at least one dose of a Covid vaccine so far.
The rollout is currently targeting elderly people and those with co-morbidities, but is expected to expand further soon.
The government in Maharashtra has put Nagpur district, which has the country's second-highest active caseload, under lockdown. It is the second lockdown in the state, which currently has the highest number of active and confirmed cases in India.
Other districts have followed with restrictions such as night curfews and closure of markets to stem the rise in cases.
"Until most of society has built up defence against the virus, we have to observe precautions because we can still get it and pass it on," Dr Reddy says.