CHIANG MAI — Chiang Mai was named the world’s most polluted city on Monday, as smoke from more than 600 wildfires blanketed the northern region, prompting authorities to launch aerial water-dropping operations in an attempt to quell the blazes.

Forest Fires Blanket Chiang Mai with Air Pollution

Satellite imagery revealed hundreds of “hotspots” across Northern Thailand and beyond the border, with thick smoke rolling into urban areas and reducing visibility to a dense, hazardous haze.

Residents Pay the Price

“I’ve already been hospitalized once because of lung damage from this dust,” said Natcha Utamang, a resident of Doi Saket who now keeps three air purifiers running in her home. “The toll this takes is severe. Those setting these fires need to stop.”

Health officials have urged residents to wear N95 masks and stay indoors as the annual “burning season” continues to choke the province with worsening air quality.

ค่ามลพิษทางอากาศเฉลี่ยในเชียงใหม่สัปดาห์นี้อยู่ที่ 37 µg/m³ ซึ่งเทียบเท่ากับการสูบบุหรี่ประมาณ 11 มวน 🌀 @grahamjonesy @ElephantNatureP @TSethawut @samuraiweedth pic.twitter.com/m3a8FiC3bJ

— Chiang Mai Air Pollution Monitor (@BREATHEChiangM_) March 29, 2026

The average air pollution in Chiang Mai this week is 37 μg/m3, which is equivalent to smoking about 11 cigarettes.

Hazardous Readings

At 10:00am Monday, Chiang Mai topped IQAir’s real-time global pollution index, recording a hazardous US AQI of 263 with PM2.5 levels hitting 188 micrograms per cubic meter — far exceeding World Health Organization safety guidelines.

Helicopters Deployed

Authorities have dispatched helicopters to drop water on fires in mountainous areas, though officials concede the scale of the crisis makes containment difficult. The blazes stem from a combination of natural conditions and agricultural burning, a long-standing practice used to clear land for planting.

A Recurring Crisis

Northern Thailand’s “burning season” runs from February to April each year, when dry weather, farmland fires and smoke drifting across borders push air quality to dangerous extremes. Despite repeated government efforts to curb the problem, Chiang Mai continues to rank among the world’s most polluted cities year after year.

Air pollution affects hotel bookings in Chiang Mai

For residents like Natcha, the crisis is no longer a seasonal headline — it is a recurring health threat with no end in sight.

-Thailand News (TN)