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.
The worst cities for PM2.5 over the 30 days to 15 Apr 2026: Mae Sai 125.0 µg/m³, Chiang Khong 124.9 µg/m³ and Ban Houakhoua 124.9 µg/m³.
- 1Mae SaiThailand125.0
- 2Chiang KhongThailand124.9
- 3Ban HouakhouaLaos124.9
- 4GurugramIndia113.5
- 5PhayaoThailand101.3
- 6ChangchunChina98.2
- 7Bueng KanThailand95.9
- 8PakxanLaos95.9
- 9Chiang RaiThailand95.0
- 10VientianeLaos94.0
- 11NanThailand91.4
- 12LoniIndia90.3
- 13LampangThailand82.8
- 14FaridabadIndia82.6
- 15LamphunThailand82.3
- 16SiddharthanagarNepal81.0
- 17DādriIndia80.5
- 18BawānaIndia79.6
- 19PhraeThailand78.9
- 20Charkhi DādriIndia77.9
+ 3,103 more cities, the next at 76.0 µg/m³
Not counted on this day, too few days measured: Bishkek since 13 Apr 2026, Lebedinovka since 10 Apr 2026, Kojomkul since 5 Apr 2026 and 2 more cities.
Cities counted each 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 reader for China's network. Turkey's network doesn't answer requests from outside the country, so we can't read it. Most cities there are missing from this board, not clean. Why.