Delhi's air quality remains severe, prompting GRAP-III restrictions under which stringent ban will be put in place on construction and demolition activities among others.

GRAP stage 3 will come into force at 8am on Friday. The Delhi government announced that classes for primary schools will be shifted to online.

Delhi sees a major spike in air pollution every winter due to several factors, including the burning of farm waste in the adjoining states of Haryana and Punjab.

Delhi air quality plummets to alarming levels every year in the winter. The air quality in the capital remains in the 'severe' category prompting the authorities to impose the third stage of GRAP.

Every year, Delhi and northern states battle hazardous air during the winter months of October to January due to plummeting temperatures, smoke, dust, low wind speed, vehicular emissions and crop stubble burning. This time, experts say that the condition is likely to get worse in the coming days.

Air pollution in India's national capital increased to 'severe' on an official index on Wednesday for the first time this season as temperatures and wind speeds dropped, reducing visibility and affecting some flights.

Air pollution choking New Delhi has ground outdoor work to a halt and disrupted air travel in the Indian capital.

The GRAP 3 curbs in Delhi include ban on demolition and construction activities, and entry of certain vehicles inside Delhi-NCR, among other curbs, to prevent further deterioration of air quality.

On Wednesday, the national capital's air quality took a serious turn for the worse, with the Air Quality Index (AQI) skyrocketing to a staggering 418. This alarming number puts the capital squarely in the 'severe' category,