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 30 days to23 Apr 2023 That day's board

The worst cities for PM2.5 over the 30 days to 23 Apr 2023: Mae Sai 281.8 µg/m³, Chiang Rai 189.4 µg/m³ and Chiang Mai 127.8 µg/m³.

  1. 1Mae SaiThailand281.8
  2. 2Chiang RaiThailand189.4
  3. 3Chiang MaiThailand127.8
  4. 4DhakaBangladesh111.5
  5. 5LoeiThailand87.7
  6. 6KathmanduNepal78.0
  7. 7Bueng KanThailand72.8
  8. 8PakxanLaos72.8
  9. 9BamakoMali72.4
  10. 10LahorePakistan70.1
  11. 11SukhothaiThailand66.4
  12. 12UttaraditThailand65.1
  13. 13TlaquepaqueMexico62.0
  14. 14BeijingChina61.7
  15. 15DelhiIndia60.4
  16. 16Bang Khun ThianThailand56.6
  17. 17PhichitThailand55.5
  18. 18PhetchabunThailand55.0
  19. 19ShenyangChina54.7
  20. 20Nong Bua LamphuThailand54.1

+ 1,743 more cities, 53.8 µg/m³ and below

Not counted on this day, too few days measured: Alexandria since 20 Apr 2023, N'Djamena since 20 Apr 2023, Mae Sot since 19 Apr 2023 and 26 more cities. Days missing from the source archive fall in this window, so fewer countries are counted.

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.