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 24 Apr 2026: Laos 110.5 µg/m³, India 35.3 µg/m³ and Pakistan 34.6 µg/m³.
- 1Laos3 cities110.5
- 2India239 cities35.3
- 3Pakistan13 cities34.6
- 4Thailand85 cities31.5
- 5Kazakhstan4 cities30.2
- 6Chile48 cities26.5
- 7Peru6 cities23.9
- 8South Korea141 cities19.5
- 9Taiwan44 cities17.5
- 10Serbia7 cities16.8
- 11Mexico51 cities16.0
- 12Hong Kong13 cities15.9
- 13Malta5 cities15.6
- 14Senegal4 cities14.3
- 15North Macedonia15 cities13.3
- 16Romania28 cities11.5
- 17Hungary13 cities11.4
- 18Slovakia42 cities11.4
- 19Italy9 cities10.6
- 20Japan575 cities10.0
+ 27 more countries, 9.4 µg/m³ and below
- 37United States866 cities6.3
Not counted on this day, too few cities measured: Poland since 23 Apr 2026, Ghana since 15 Apr 2026, Bosnia and Herzegovina since 13 Apr 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.