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 7 days to 6 Apr 2026: Laos 133.4 µg/m³, Kazakhstan 35.3 µg/m³ and Pakistan 30.6 µg/m³.
- 1Laos3 cities133.4
- 2Kazakhstan4 cities35.3
- 3Pakistan13 cities30.6
- 4Thailand85 cities30.3
- 5India243 cities30.1
- 6Chile47 cities22.7
- 7Peru6 cities22.3
- 8South Korea141 cities19.6
- 9Ghana3 cities19.3
- 10Serbia7 cities19.3
- 11Senegal4 cities17.5
- 12Mexico52 cities15.6
- 13Hong Kong13 cities15.5
- 14North Macedonia14 cities14.8
- 15Taiwan44 cities14.3
- 16Romania28 cities13.1
- 17Poland60 cities12.8
- 18Hungary13 cities10.1
- 19Slovakia42 cities10.1
- 20Latvia3 cities10.0
+ 29 more countries, 8.5 µg/m³ and below
- 37United States874 cities5.7
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 6 Apr 2026, Philippines since 6 Apr 2026, Kyrgyzstan since 25 Mar 2026 and 2 more countries.
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.