A day after the Diwali festivities, the air pollution levels in Delhi-NCR on Friday deteriorated further to the 'very poor' category with a blanket of toxic smoke engulfing the whole region.

According to the Central Pollution and Control Board CPCB, the average air quality index (AQI) in the capital Delhi till 7:30 a.m. remained at 361.

In most areas of the national capital, the AQI level remained between 300 and above 400.

The AQI was 353 in Alipore, 395 in Anand Vihar, 387 in Ashok Vihar, 392 in Bawana, 395 in Burari Crossing, 395 in Chandni Chowk, 371 in Mathura Road, 372 in Dr Karni Singh Shooting Range, 375 in IGI Airport, 334 in ITO, 390 in Jahangirpuri, 343 in Jawaharlal Nehru Stadium, 314 in Lodhi Road, 374 in Mundka, 329 in Najafgarh, 385 in Nehru Nagar, 390 in North Campus, 352 in Dwarka, 369 in Okhla Phase 2, 392 in Punjabi Bagh, 388 in Shadipur, 395 in Sonia Vihar, 314 in Sri Aurobindo Marg, and 389 in Wazirpur.

The air quality in the National Capital Region continued to be a concern as it remained in the ‘very poor’ category a day after the festivities. People celebrated Diwali defying a ban on firecrackers in Delhi thus contributing to the poor air conditions.

The air pollution levels in surrounding cities also increased after a night of firecrackers bursting by people. In the NCR city of Faridabad, the AQI was 244; in Gurugram it was 348; in Ghaziabad 381; in Greater Noida 370; and in Noida, the air pollution level was 295.

An AQI between zero and 50 is considered 'good'; 51 to 100 'satisfactory'; 101 to 200 'moderate'; 201 to 300 'poor'; 301 to 400 'very poor; and 401 to 500 'severe'.

Delhi has been witnessing worsening air quality for the past few weeks, primarily because of stubble burning and poor wind circulation.

The Delhi government on October 14 imposed a ban on the production, storage, sale, and use of firecrackers across the city, effective until January 1, 2025. The government has also deployed 377 enforcement teams to tackle this, but many people defied the ban and burst firecrackers

The pollution levels at many of the pollution measuring stations of Delhi-NCR touched a peak around midnight.