All shops and businesses will be shut and movement will be limited to essential services.
Announcing a six-day lockdown in Delhi from 10 pm tonight to 5 am next Monday, Chief Minister Arvind Kejriwal said the move was necessary as rising Covid cases had severely strained the city's resources and its health system was at a tipping point.
Delhi is the worst-hit city in India with 25,500 fresh cases on Sunday and almost one-third of those tested returning positive. In the last 24 hours, the number of cases remain high despite a dip -- 23,500.
"Delhi's health system is at a breaking point. I will not say it has collapsed but the Covid situation is pretty critical," Arvind Kejriwal said in a televised address, asserting that the lockdown decision was not an easy one.
"I have always been against a lockdown. I believe the lockdown will not finish the virus, but it will reduce the transmission rate. It will give us time to boost our infrastructure. We will use this week-long lockdown to improve our healthcare," he added.
Delhi is facing acute shortages of hospital beds, medical oxygen supplies and key medicines such as the anti-viral Remdesivir, said Mr Kejriwal.
"If we don't enforce a lockdown now, Delhi could be staring at a "bigger disaster," he explained.
All shops and businesses will be shut and movement will be limited to essential services.
There have been similar measures in other parts of India, including in Maharashtra.
On Sunday, Delhi recorded the biggest jump in its daily Covid tally with 25,462 fresh cases and a positivity rate of nearly 30 per cent, which means almost every third sample being tested in the city is turning out positive.
A weekend curfew enforced to "break the chain of transmission" ended this morning, giving the people of Delhi a few more hours to stock up.
Mr Kejriwal met with Lieutenant Governor Anil Baijal this morning.
It was also decided in the meeting that Mr Baijal, who represents the centre in Delhi, would write to the central government for more beds in the city. The Lieutenant Governor is also expected to write to the Uttar Pradesh Chief Minister for more oxygen.
Mr Baijal asked in the meeting that concerns related to migrant labourers be looked into. Migrant workers were the worst hit this time last year when the nation went into a lockdown, leaving thousands deprived of their earnings and homes.
"I appeal to all that this is a small lockdown of six days. Please don't leave Delhi. I assure you that the government will look after you," said the Chief Minister.
As in the weekend curfew order, auditoriums, restaurants, malls, gyms and spas remain shut and movie theatres are allowed only with a third of their capacity. All gatherings -- social, religious or political - are banned.
Mr Kejriwal has been saying that the rising cases have been exerting tremendous pressure on the national capital's health infrastructure.
"The situation is very serious and worrisome. Cases have gone up really fast. That is why we are facing shortages even though everything seemed under control until a few days ago. But the speed at which this corona is growing, no one knows where its peak will be," he said in a virtual address on Friday.