Delhi's 'very poor' AQI on Diwali day and day after is worst in five years

Diwali celebrations are over and now the concern is about the air quality in the city and its adjoining areas like Noida, Gurugram and Faridabad. According to Central Pollution Control Board (CPCB), Delhi recorded its most polluted Diwali in five years on Sunday (Nov 8) with average Air Quality Index settling at 376. The morning after was only marginally better at 371, recorded at 10 am on Monday. However it still falls under the 'very poor' category.

The Monday AQI was the highest for a post-Diwali day since 2021, while the Diwali-day AQI of 376 was the highest recorded on the day of the festival since 2021, when it had settled at 382.

Of the 51 monitoring stations that recorded data, 14 were in the 'severe' category, four in the 'poor' category and the remaining 33 in the 'very poor' category.

What are the AQI categories?

0-50: Good

51-100: Satisfactory

101-200: Moderate

201-300: Poor

301-400: Very Poor

401-500: Severe

However, it is to be noted that Diwali does not fall on the same month every year. For instance, the celebration was on November 8 this year, on October 20 in 2025, October 31 in 2024, November 12 in 2023, October 24 in 2022 and November 4 in 2021.

It is important to mention the month of Diwali as farm fire in neighbouring Haryana and Punjab is another major reason for AQI to deteriorate in Delhi. The stubble burning on farms usually begins by the end of October.

The average AQI on Diwali in 2025 was 345, while in 2024 and 2023 it was at 328 and 218, respectively. In 2022 the AQI stood at 312 and 382 in 2021.