Despite Delhi's blanket ban on the storage, sale and use of firecrackers on Diwali, the Air Quality Index (AQI) of the national capital stood at 323 on Tuesday under the "very poor" category.

On Monday, the AQI was registered at 312, which was the lowest in four years and the second-best in seven years for a Diwali day.

As per data, the AQI last year was 382, 414 in 2020 and 337 in 2019.

At around 6 a.m. on Tuesday, the number increased to 323, while the PM 2.5 levels were five to six times higher than the national standard.

Meanwhile, the air quality also slipped into the "very poor" category in neighbouring Gurgaon, Noida and Faridabad.

The level of AQI between zero to 50 is considered "good"; 100 is "satisfactory"; 101 to 200 is "moderate"; 201 to 300 is "poor"; 301 to 400 is "very poor"; while 401 to 500 falls in the "severe" category.

Despite the blanket ban, the national capital witnessed bursting of crackers all through Monday night.

Several videos of people bursting firecrackers were doing the rounds on social media, leaving a question on the implementation of the ban imposed by the Delhi government and the Delhi Police failing to stop the violations.

Meanwhile, 201 emergencies and fire-related calls were received by the fire department on Monday, 32 per cent higher than previous year.

"Many fires resulted from lighting diyas and a large number of instances were of garbage catching fire, probably because crackers fell on them," said a fire department official. (SJ/IANS)