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 to10 Apr 2023 That day's board

The worst cities for PM2.5 over the 7 days to 10 Apr 2023: Mae Sai 251.7 µg/m³, Chiang Rai 164.2 µg/m³ and N'Djamena 156.1 µg/m³.

  1. 1Mae SaiThailand251.7
  2. 2Chiang RaiThailand164.2
  3. 3N'DjamenaChad156.1
  4. 4Chiang MaiThailand147.1
  5. 5LoeiThailand127.5
  6. 6DhakaBangladesh119.1
  7. 7Tha BoThailand103.2
  8. 8VientianeLaos103.2
  9. 9LahorePakistan77.9
  10. 10Nong Bua LamphuThailand74.3
  11. 11SukhothaiThailand71.7
  12. 12BamakoMali70.0
  13. 13UttaraditThailand69.8
  14. 14Bueng KanThailand68.7
  15. 15PakxanLaos68.7
  16. 16KathmanduNepal66.9
  17. 17ShenyangChina65.7
  18. 18AlexandriaEgypt65.2
  19. 19OsornoChile64.7
  20. 20Bang Khun ThianThailand61.3

+ 1,756 more cities, 58.9 µg/m³ and below

Not counted on this day, too few days measured: Phayao since 10 Apr 2023, Lamphun since 10 Apr 2023, Lampang since 10 Apr 2023 and 22 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.