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 to19 Apr 2023 That day's board

The worst cities for PM2.5 over the 30 days to 19 Apr 2023: Chiang Rai 187.7 µg/m³, N'Djamena 146.2 µg/m³ and Chiang Mai 129.1 µg/m³.

  1. 1Chiang RaiThailand187.7
  2. 2N'DjamenaChad146.2
  3. 3Chiang MaiThailand129.1
  4. 4DhakaBangladesh113.7
  5. 5BamakoMali75.3
  6. 6KathmanduNepal73.4
  7. 7Bueng KanThailand73.2
  8. 8PakxanLaos73.2
  9. 9LahorePakistan73.1
  10. 10SukhothaiThailand66.2
  11. 11BeijingChina65.9
  12. 12DelhiIndia63.6
  13. 13UttaraditThailand63.0
  14. 14TlaquepaqueMexico60.7
  15. 15ShenyangChina57.1
  16. 16Bang Khun ThianThailand55.1
  17. 17Ubon RatchathaniThailand53.8
  18. 18PhichitThailand53.2
  19. 19AlexandriaEgypt50.7
  20. 20HyderabadIndia50.6

+ 1,731 more cities, 50.2 µg/m³ and below

Not counted on this day, too few days measured: Mae Sot since 19 Apr 2023, Mae Sai since 19 Apr 2023, Si Sa Ket since 19 Apr 2023 and 33 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.