Air pollution during Diwali typically peaks late at night and early morning, as cooler air traps pollutants near the ground. Studies show PM2.5 levels rising sharply after 11pm, with levels exceeding standards until early morning. For example, Delhi's PM2.5 levels on Diwali day in 2020 were eight times India's 24-hour standard. Noise pollution also peaks during firecracker hours, with sound levels often exceeding legal limits.