The air quality in Delhi has been on a slump since Thursday evening as bursting of firecrackers went unchecked across the national capital on Diwali.

The Air Quality Index in most areas of Delhi has been in the 'hazardous' category as people complained itchiness in eyes and nasal tract.

Delhi's AQI at 8am on Saturday was 449, which is 'severe'. In the adjoining areas of Noida, Gurugram, Ghaziabad and Greater Noida, the AQI was even higher.

Delhi's particulate matter (PM) concentration stood at at 457-the highest levels in the past three years - on Friday morning. PM2.5 was recorded to be 341 per cubic metre at Delhi's Jantar Mantar, the safe limit, as per WHO,being 25.

Delhi has been grappling with air pollution crisis around Diwali time, with the situation being worsened by the stubble burning in the neighboring states of UP and Haryana.

Meanwhile, the efficacy of smog towers and other anti-pollution initiatives of the AAP-led government in Delhi have come under question.