Chiang Mai, a popular tourist city in northern Thailand, is suffering from some of the worst air pollution levels in the world. Residents are reporting nosebleeds, rashes and allergy symptoms, with many preparing to leave the city.
Air quality monitoring agency IQAir classified Chiang Mai as one of the most polluted cities in the world, BBC reported on Tuesday. A total of 4,750 fire hotspots were detected across Thailand the previous day, and fine particulate matter (PM2.5) concentrations in Chiang Mai soared to "very unhealthy" levels that morning.
The damage has been concentrated among infants, young children and the elderly. Thirayut Wongsantisuk, 41, who moved to Chiang Mai in 2010, said his two six-year-old daughters frequently suffer nosebleeds. "If something happens to my children, I would regret it for the rest of my life. I'm considering moving," he said.
Benjamas Jaipakan, 35, a public school teacher, temporarily evacuated her four-year-old son to the neighboring Phayao province. "I don't know how much longer my child's lungs can endure this," she said, adding that she is also considering leaving Chiang Mai permanently.
The main culprits behind the pollution are the dry climate and the rural practice of crop burning. Farmers burn weeds and agricultural residue before planting season, and the fires combine with dry atmospheric conditions to spread into wildfires, generating explosive levels of particulate matter.
Around 1,700 residents filed a lawsuit in July 2023 against government agencies and the former prime minister, alleging they had neglected their duty to address air pollution. The plaintiffs claimed the pollution is shortening their life expectancy by approximately five years.
The Thai government has closed national parks with high fire risk and ordered the immediate arrest of illegal arsonists. Those convicted face up to 20 years in prison and fines of up to 2 million baht (approximately 75 million won, or about $54,000).
The issue is particularly relevant for South Koreans. According to data from the Tourism Authority of Thailand, Korean visitors topped the list of foreign arrivals at Chiang Mai International Airport this year with 34,965 entries, surpassing Chinese visitors at 34,894.
Chiang Mai set an all-time record by attracting a total of 12 million visitors in 2025, including 4 million international tourists. South Korea ranked second among the top five source countries.
Chiang Mai is especially popular among Koreans as a destination for month-long stays, thanks to its cool weather and low cost of living. Experts say travelers should check air quality indexes before planning trips to the city.