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 to23 Apr 2024 That day's board

The worst cities for PM2.5 over the 7 days to 23 Apr 2024: N'Djamena 169.1 µg/m³, Kathmandu 91.0 µg/m³ and Chiang Khong 89.3 µg/m³.

  1. 1N'DjamenaChad169.1
  2. 2KathmanduNepal91.0
  3. 3Chiang KhongThailand89.3
  4. 4Ban HouakhouaLaos89.3
  5. 5Santa MaríaPeru78.4
  6. 6Chiang MaiThailand72.3
  7. 7Ubon RatchathaniThailand72.0
  8. 8NanThailand69.6
  9. 9PhayaoThailand66.5
  10. 10KalasinThailand65.2
  11. 11UttaraditThailand62.5
  12. 12Mae SaiThailand62.4
  13. 13LampangThailand61.6
  14. 14DhakaBangladesh61.2
  15. 15CoyhaiqueChile58.9
  16. 16MukdahanThailand58.3
  17. 17LamphunThailand58.1
  18. 18Tha BoThailand57.5
  19. 19VientianeLaos57.5
  20. 20PhraeThailand54.6

+ 2,692 more cities, 53.1 µg/m³ and below

Not counted on this day, too few days measured: Lahore since 18 Apr 2024, Toluca since 29 Mar 2024 and Tlaquepaque since 2 Mar 2024.

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.