Studies show that PM2.5 levels rise by 29–60% during Diwali compared to pre-Diwali levels. In Delhi, the average AQI increased from 296 to 353 after Diwali in 2025, with PM2.5 levels peaking at 483 micrograms per cubic metre on Diwali day in 2020—eight times India's 24-hour standard. The pollution is most severe late at night and early morning, as cooler air traps particles near the ground. Checking the live Air Quality Index (AQI) on the CPCB Sameer app can help plan safer activities.