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

Diwali leads to high AQI in Delhi

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.

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.

Mixed trends across states

The pollution spike coincides with a rise in stubble-burning incidents in Punjab, even as Haryana reported a sharp decline in such fires. Local sources, including vehicular emissions and construction dust, also could have played a larger role in the spike this year.

Curbs tightened under GRAP

In response, authorities have tightened restrictions under the Graded Response Action Plan (GRAP). The second stage of the plan, which limits construction and industrial activity, was activated earlier this week.

"Delhi is bearing the brunt of pollution from neighbouring states, stubble is burnt despite the Supreme Court's stricture," Manjinder Singh Sirsa, Delhi’s environment minister, said on October 21.