Northern Thailand faces hazardous air pollution as crop burning and forest fires blanket the region, pushing Chiang Mai to top global pollution rankings.

BANGKOK: Swathes of northern Thailand choked under a blanket of hazardous haze on Tuesday, with the tourist hub of Chiang Mai ranking as the world’s most polluted major city.

The crisis, driven by agricultural burning and forest fires, saw PM2.5 pollutant levels in Chiang Mai hit 110 micrograms per cubic metre.

This far exceeds the World Health Organization’s recommended limit of 15 micrograms for most days of the year.

The situation was even more severe in Pai, a popular backpacker destination in Mae Hong Son province.

Some monitors recorded PM2.5 levels there surpassing 600 micrograms per cubic metre.

A cafe worker in Pai, who gave only her first name Dao, said this year’s pollution was unprecedented.

“I’ve never seen this much pollution in Pai before,” she told AFP.

She shared photos showing the region’s usually green hills completely obscured by a grey-brown haze.

Long-time British resident and organic farmer George Wolstencroft called the haze “probably the worst I’ve ever seen it”.

He described the situation as a “humanitarian disaster” with smoke visible less than 50 metres away.

The Chiang Mai governor’s office stated that illegal burning and forest fires in national parks were causing the hazardous conditions.

Thailand’s Geo-Informatics and Space Technology Development Agency recorded a 2026 high of 4,750 fire hotspots across the country on Monday.

It also detected more than 5,000 hotspots across the border in Myanmar, with thousands more in neighbouring Laos, Cambodia, Vietnam and Malaysia.

The spike in pollution coincides with warnings from clean air activists about a stalled clean air bill.

The Thailand Clean Air Network said the legislation, which would enshrine the right to breathable air, risks dying in parliament if not revived soon.

More than 10 million people required treatment for pollution-related health problems in Thailand in 2023, according to the health ministry.

 The Sun Malaysia