2026 Chiang Mai Smog
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| Date | January 2026—present |
|---|---|
| Location | Northern Thailand and Chiang Mai province |
| Type | Seasonal air pollution and wildfires |
The 2026 Chiang Mai smog is an ongoing air pollution event affecting Northern Thailand and Chiang Mai province beginning in January 2026 as a result of forest fires in Northern Thailand and Myanmar.[1][2] The city was ranked as having the world's most polluted air multiple times throughout March 2026.[3][4]
1 April 2025
On 1 April 2026, Chiang Mai municipality declared several areas as disaster zones following PM2.5 levels in some districts exceeding 300 micrograms per cubic meter, almost 10 times higher than the government's safety standard.[5][6]
2 April 2026
As of 2 April 2026, Chiang Mai was ranked by US AQI+ as the world's second most polluted city, with an AQI of AQI 231 (purple).[7]
4 April 2026
On 4 April 2026, Thailand's Ministry of Interior declared Chiang Mai, Lamphun, and Phayao provinces as emergency disaster zones as a result of hazardous air quality.[8] The declaration will aloow provincial governors to disburse emergency funds.[8] Disaster declarations were also made in Pai and Mae Sariang districts of Mae Hong Son province.[9]
Also on 4 April, visibility in Chiang Mai at Nakornping Hospital in Mae Rim district decreased dramatically.[10]
7 April 2026
On 7 April 2026, Chiang Mai continued to be ranked as having the world's worst air quality.[11]
8 April 2026
On 8 April 2026, Third Army Area commander lieutenant general Worathep Bunya chaired an operational planning meeting in Mae Rim and subsequently joined an aerial firefighting mission in Chiang Mai.[12]