On Saturday, levels of harmful PM 2.5 particles topped 300 on the air quality index. That number is more than 10 times the safe daily limit set by the World Health Organization.
A reading over 300 for 48 hours would initiate emergency measures in the capital, including the closure of primary schools and severe traffic restrictions.
The Central Pollution Control Board on Friday told New Delhi residents to "limit outdoor activities and minimise their exposure" and advised government authorities to prepare "for implementation of measures under 'emergency' category".
It added the poor air quality would likely run until 18 November due to "low winds with calm conditions during the night".
On Saturday, the Supreme Court suggested imposing a pollution lockdown on Delhi to help with the air quality crisis. "How will we live otherwise?" Chief Justice N.V. Ramana said.
The burning of agricultural waste in Delhi's neighbouring states -- largely behind the megacity's pollution levels every winter -- has continued despite a Supreme Court ban.
The number of farm fires this season has been the highest in the past four years, according to government data.
At the COP26 global climate summit this month, prime minister Narendra Modi made it clear that carbon emissions-cutting pledges from India and other developing nations would require finance from rich, historic emitters.
A 2020 report by Swiss organisation IQAir found that 22 of the world's 30 most polluted cities were in India, with Delhi ranked the most polluted capital globally.
The same year, the Lancet said 1.67 million deaths were attributable to air pollution in India in 2019, including almost 17,500 in the capital.