SmogRank / Countries / Thailand / 2026

Most polluted cities in Thailand, 2026

7 cities in Thailand ranked by their average PM2.5 so far (273 of 365 days); 7 above the WHO annual guideline (5.0 µg/m³). Worst: Chiang Mai at 31.3 µg/m³, #119 of 2,181 cities in the world. Cleanest: Bang Pakong at 16.8. A city needs measurements on 70% of the days to be ranked.

  1. 1Chiang Mailow-cost sensorsChiang Mai
    31.36.3×
  2. 2Uttaraditlow-cost sensorsUttaradit
    27.95.6×
  3. 3Khlong Luanglow-cost sensorsPathum Thani
    25.25.0×
  4. 4Sai Mailow-cost sensorsBangkok
    21.44.3×
  5. 5Bangkoklow-cost sensorsBangkok
    20.84.2×
  6. 6Ban Khlong Prawetlow-cost sensorsBangkok
    19.94.0×
  7. 7Bang Pakonglow-cost sensorsChachoengsao
    16.83.4×
Good0–9.0
Moderate9.1–35.4
Sensitive groups35.5–55.4
Unhealthy55.5–125.4
Very unhealthy125.5–225.4
Hazardous225.5+

All cities in the world, 2026 · Thailand now