SmogRank / History / City race

Cities, worst air first, day by day

Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.

CountriesCities
The 7 days to3 Apr 2026 That day's board

The worst cities for PM2.5 over the 7 days to 3 Apr 2026: Mae Sai 189.0 µg/m³, Chiang Khong 177.7 µg/m³ and Ban Houakhoua 177.7 µg/m³.

  1. 1Mae SaiThailand189.0
  2. 2Chiang KhongThailand177.7
  3. 3Ban HouakhouaLaos177.7
  4. 4PhayaoThailand146.7
  5. 5ChangchunChina130.1
  6. 6Chiang RaiThailand123.0
  7. 7GurugramIndia122.0
  8. 8RohtakIndia113.3
  9. 9LampangThailand109.3
  10. 10NanThailand108.1
  11. 11LamphunThailand107.1
  12. 12DādriIndia101.1
  13. 13PhraeThailand100.8
  14. 14LoniIndia100.7
  15. 15MānesarIndia98.7
  16. 16VientianeLaos97.8
  17. 17Charkhi DādriIndia94.0
  18. 18FaridabadIndia88.9
  19. 19BawānaIndia84.1
  20. 20Bueng KanThailand79.3

+ 3,096 more cities, 79.3 µg/m³ and below

Not counted on this day, too few days measured: Dhāruhera since 29 Mar 2026, Bahadurgarh since 27 Mar 2026, Rahim Yar Khan since 26 Mar 2026 and 2 more cities.

30 days7 days
GoodModerateSensitive groupsUnhealthyVery unhealthyHazardousWHO 24-hour guideline, 15 µg/m³Fades where it stood: not counted that day

A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.

Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.