Gujarat, the home state of Indian Prime Minister Narendra Modi, became the latest to tighten coronavirus curbs on Wednesday as daily infections in the country surged to a record high, with almost 116,000 new cases in 24 hours.
Experts blame the country's latest wave on people ignoring guidelines and attending huge religious and political events, as well as weddings and cricket matches in recent months.
India has now recorded 12.8 million cases, the third-highest behind the US and Brazil, although those countries have much smaller populations.
More than 166,000 Indians have died of Covid-19
On Wednesday, Gujarat in western India, home to 63.8 million people, extended nightly restrictions to 20 cities and banned large social and political gatherings.
"We have also extended the time of night curfew from 8pm to 6am ... this will be in force until April 30," Gujarat chief minister Vijay Rupani said.
Gujarat has 17,348 active Covid-19 cases.
In Maharashtra, the worst-hit state and home to megacity Mumbai, authorities imposed a night curfew and weekend lockdowns that are due to begin on Friday evening.
According to the Ministry of Health and Family Welfare, seven of the 10 districts with the highest number of active cases in the country are in Maharashtra.
On Tuesday, 55,469 new infections were reported, the second-highest tally after a surge on April 4.
Active cases in Maharashtra, home to 123 million, stand at 473,693.
More than 30 million residents of New Delhi were placed under a night-time curfew on Tuesday as the government tried to curb rising infections. There are 17,332 active cases in Delhi.
The northern state of Punjab on Wednesday ordered a ban on political gatherings and extended a night-time curfew to the entire state while capping numbers at indoor funerals and weddings to 50 guests and 100 for outdoors.
UK variant suspected
Chief minister Amarinder Singh said it was also a "matter of concern that over 85 per cent of cases in Punjab are of the UK strain, which is more contagious and virulent".
Press reports say that hospitals are beginning to struggle, particularly in Maharashtra. One Pune clinic that ran out of hospital rooms is reportedly giving oxygen support to patients in a makeshift waiting area.
The All India Institute of Medical Sciences, one of Delhi's biggest government hospitals, will from Thursday end walk-in consultations to minimise infections, local reports said.
The government has so far shied away from reimposing a nationwide lockdown after a shutdown in March 2020 – one of the world's toughest – caused widespread human and economic misery.
Many Indians lowered their guard after infections slowed sharply in late 2020, with huge crowds thronging religious festivals such as the Kumbh Mela, which on one day last month drew three million devotees.
Spectators were also allowed at cricket matches between India and England in Gujarat, while political rallies for state elections drew huge crowds, including an estimated 800,000 at one event hosted by Mr Modi.
India has so far administered almost 90 million vaccine shots but experts say that the government's target to inoculate 300 million people by August risks being missed with many scared to get the injections or complacent about the virus.