Diwali fireworks push Delhi’s air quality to four-year low; AQI surges 49%

Crackers lit up Delhi’s skies over Diwali, but the celebrations left the city and its suburbs blanketed in smog, pushing air pollution to a four-year high.

Air quality also saw its sharpest decline during Diwali in four years from the pre-Diwali period, with the Air Quality Index (AQI) jumping 49 percent on October 20–21 from the previous eight-day average, data released on October 21 showed.

The capital’s AQI climbed to 351, marking the first ‘severe’ reading of the season and one of the worst Diwali levels since 2021, when the index crossed 460. In comparison, the eight-day average preceding October 20 and 21 stood at 233, indicating a steep deterioration within just two days.

Sharpest Diwali spike since 2021

Historically, Delhi’s air quality worsens during Diwali week, but the nearly 50 percent surge this year is among the steepest since 2021, when a similar jump was recorded. Typically, AQI levels rise between 10 and 25 percent from the week before Diwali to the festival day.

This year’s Diwali-day AQI (351) was higher than last year’s 339, though still below 2021’s 462 and 2020’s 435. Pollution levels may worsen further if stubble burning intensifies post-Diwali and cooler winter temperatures trap pollutants closer to the ground.