Its health ministry said 3,689 people had died within the past 24 hours.
Prime Minister Narendra Modi met the health minister on Sunday morning to review the crisis.
Hospitals are battling to treat patients amid a chronic shortage of beds and medical oxygen.
Amid the crisis, vote counting started on Sunday for elections held in five states: Assam, West Bengal, Tamil Nadu, Kerala and Puducherry.
The outcomes are being watched for signs of how the pandemic has affected support for Mr Modi and his Hindu nationalist party, the BJP. He has been criticised for allowing rallies to take place during polling in March and April.
Results so far from West Bengal, where Mr Modi had been seeking a win, instead suggest the TMC party of fierce Modi critic Mamata Banerjee will comfortably retain power.
