The Indian capital on Tuesday imposed an immediate night curfew a day after the nation posted a record coronavirus surge, with financial hub Mumbai also introducing similar restrictions.
Alarm has grown since India passed more than 100,000 new cases in a single day for the first time on Monday.
New Delhi, home to 25 million people, and other major cities have all ordered a clampdown on public movement.
The Delhi regional government said the "sudden increase in COVID-19 cases" and "high positivity rate" meant a night curfew was needed.
A street is pictured in New Delhi during a night curfew. AFP
The ban will be in place from 10 pm to 5am with only essential services or people travelling to and from vaccination centres allowed on the streets.
But Delhi residents spoke to expressed doubts about how effective the night-time restrictions would be in reducing the spread of the virus.
"Most people who are going to get COVID are going to get it in the day when they are out and about... The night curfew is not going to change anything much," financial consultant Arvind Khanna, 62, told reporters.
"India is a very populated country and Delhi is one of the most populated cities in the world. So there really is no effective way. People just need to follow the rules -- wear a mask, use sanitiser, keep the distance," added 18-year-old student Angel Miyamoto.
Delhi reported 3,548 new positive cases on Monday, still below its peak of nearly 9,000 in November, when it was one of the worst-hit cities across the nation of 1.3 billion people.
The government has so far shied away from reimposing a repeat of the nationwide restrictions imposed in March last year -- one of the world's toughest lockdowns -- as it seeks to revive the devastated economy.
Police officers patrol in front of closed shops at a market area in New Delhi. Reuters
But India's wealthiest state Maharashtra, which includes Mumbai, on Sunday announced a weekend lockdown and night curfew on its population of 110 million.
The state currently accounts for more than half of new cases reported each day nationwide.
Vinod K Paul, a member of the government advisory body NITI Aayog, said late Tuesday during a health briefing that the next four weeks would be very critical for the country.
India, which has the world's third-highest number of infections after the United States and Brazil, has reported almost 12.7 million cases and more than 165,000 deaths.
Single-day infections have been rising since early February, when they fell to below 9,000.
The country has recorded more than 549,000 cases in the last seven days -- an increase of 40 percent compared to the previous week.