The Prince of Wales joined the millions in the city dealing with the pollution as he wound down his tour of the Commonwealth, with smog visible in pictures of his time in New Delhi.
The problem has been compounded this year by still-weather conditions, the weather office said. The safe limit is 50.
An hour before it was 591.
PM2.5 refers to particulate matter about 30 times finer than a strand of human hair. The particles can be inhaled deep into the lungs, causing heart attacks, strokes, lung cancer and respiratory diseases. The NASA images show how Delhi, Punjab, Haryana, and states of Pakistan is covered in haze and fog.
Residents complained of headaches, coughs and smarting eyes. "I have a constant irritation in my throat".
Many people stayed at home and restaurants in some of the city's most crowded parts were deserted.More news: Lonzo Ball: No word from LiAngelo amid situation in China
"Taking a serious view of the life threatening high pollution in Delhi-NCR, the NHRC has observed that it is apparent that the concerned authorities have not taken proper steps throughout the year to tackle this hazard, which is amounting to violation of the Right to Life and Health of the residents in the region", the NHRC said.
Sudhakar said north-westerly winds were still blowing over the capital, bringing smoke-laden air to the city.
New Delhi will follow an "odd-even" scheme for five days starting Monday, in which cars will be allowed on the roads based on whether their number plates carry odd or even numbers.
A sweeping set of measures including odd-even auto rationing scheme, ban on civil construction activities, closure of schools and ban on entry of heavy vehicles except for those carrying essential commodities have been announced over the last two days to tackle the situation.
But experts said these measures were unlikely to bring immediate relief. The poisoning air chokes the Delhi and neighboring states, Punjab and Haryana.