SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 30 days to 9 May 2026: Laos 68.0 µg/m³, Pakistan 41.9 µg/m³ and India 36.6 µg/m³.
- 1Laos3 cities68.0
- 2Pakistan14 cities41.9
- 3India212 cities36.6
- 4Chile47 cities29.7
- 5Peru6 cities27.4
- 6Thailand81 cities26.7
- 7Kazakhstan4 cities19.2
- 8Mexico51 cities19.2
- 9Malta5 cities18.5
- 10Taiwan44 cities15.6
- 11Serbia8 cities15.1
- 12South Korea141 cities14.9
- 13Hong Kong13 cities14.6
- 14Malawi5 cities14.4
- 15Senegal3 cities13.3
- 16North Macedonia14 cities12.4
- 17Italy39 cities11.3
- 18Hungary13 cities11.0
- 19Slovakia42 cities10.6
- 20Romania28 cities10.5
+ 29 more countries, 9.6 µg/m³ and below
- 40United States867 cities5.7
Not counted on this day, too few cities measured: Poland since 23 Apr 2026, Ghana since 15 Apr 2026, Philippines since 8 Apr 2026 and Kyrgyzstan since 5 Apr 2026.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. 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.