Indore chokes after Diwali, air quality turns ‘very poor’:AQI hits 370, slightly below last year; PM10 and PM2.5 stay high as calm winds trap pollutants

A day after Diwali celebrations, Indore, known as India’s cleanest city, woke up to ‘very poor’ air quality, though slightly better than last year. Data from the Madhya Pradesh Pollution Control Board (MPPCB) recorded the Air Quality Index (AQI) at 370 in Chhoti Gwaltoli–Regal Square, compared to 391 during Diwali 2024. Despite the Indore Municipal Corporation’s (IMC) rapid post-Diwali cleanup drive, which removed over 1,400 tonnes of waste within hours, pollution levels remained high due to heavy overnight fireworks and calm winds that limited pollutant dispersion. Marginal improvement in PM levels According to the MPPCB data, PM2.5 concentrations dropped from 238 µg/m³ in 2024 to 210 µg/m³ in 2025, while PM10 levels decreased from 299 µg/m³ to 289 µg/m³. Other pollutants also showed improvement like NO₂ reduced from 85 µg/m³ to 69 µg/m³, CO fell from 2.2 mg/m³ to 0.9 mg/m³, and SO₂ decreased from 44 µg/m³ to 29 µg/m³. However, the overall AQI of 370 still placed Indore in the “very poor” category, just below the “severe” threshold of 400 as defined by the Central Pollution Control Board (CPCB). Weather played a major role Experts attributed the persistently poor air quality to low wind speed and humidity buildup that trapped pollutants close to the ground.
This year, wind speed was recorded at 0.6 m/s while relative humidity stands to 62%, preventing the dispersion of particulate matter. The city saw a heavy spell of fireworks late into the night. Although waste was cleared swiftly, the lack of wind didn’t allow pollutants to escape the city’s air. said Dr. Dilip Waghela, an environmentalist and former MPPCB official. Air still cleaner than last year Compared to Diwali 2024, the data suggests a marginal improvement in overall air quality. AQI dropped by 21 points, and nearly all major pollutant parameters, PM2.5, PM10, NO₂, SO₂, and CO, saw declines. The only parameters that rose were ammonia (NH₃) and ozone, both increasing slightly from 18 to 20 µg/m³ and 46 to 56 µg/m³, respectively. Temperature on Diwali night was recorded 26°C this year, indicating cooler and more humid conditions. Vehicular emissions and road dust continue to dominate A previous study by Clean Air Catalyst, a global initiative on air quality, identified vehicular pollution and road dust as Indore’s major contributors, accounting for 70% of total pollution load even under normal conditions.
Experts say that while the city’s waste management and sweeping efforts are exemplary, the next challenge lies in reducing vehicular emissions and managing road dust, particularly after large public celebrations. Clean city, but polluted skies For most of the year, Indore’s AQI remains in the ‘satisfactory’ range (51–100), but major festivals like Diwali continue to push the air quality into the ‘very poor’ or even ‘severe’ category for short durations. With 2025 showing a slight decline in pollution levels compared to 2024, officials say the focus now will be on preemptive measures, regulating firecracker use, controlling traffic emissions, and expanding green zones, to ensure that next year’s Diwali skies remain as clean as its streets.