Chiang Mai again has world's most polluted airA helicopter of the Disaster Prevention and Mitigation Department collects water from a reservoir to dump on a forest fire in Sri Lanna National Park in Mae Tang district in Chiang Mai province on Monday. (Photo: Wildfire Prevention and Mitigation Operation Centre Region 3)Chiang Mai retained its position as the city with the world's most polluted air on Tuesday, with the northern tourist hub suffering under extreme smog. The Air Quality Index (AQI) in the northern city was measured at 239, with the level of PM2.5 pollutants at 163.5 microgrammes per cubic metre, at 10am. The number of hot spots across Chiang Mai province also rose, to 303 locations from 89 on Monday, according to Gisda satellite images. The only good news from Chiang Mai was that dust pollution was expected to ease later in the day and continue to at least Thursday, according to the forecast of the weather tracking website.

Source: Bangkok Post March 31, 2026 06:38 UTC