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 14 Apr 2026: Laos 130.7 µg/m³, Pakistan 37.9 µg/m³ and India 35.0 µg/m³.
- 1Laos3 cities130.7
- 2Pakistan13 cities37.9
- 3India239 cities35.0
- 4Thailand83 cities31.7
- 5Malta5 cities30.1
- 6Chile45 cities26.3
- 7Peru6 cities24.3
- 8Serbia8 cities18.2
- 9Kazakhstan4 cities17.6
- 10Mexico54 cities17.6
- 11South Korea140 cities16.8
- 12Taiwan43 cities16.8
- 13Senegal4 cities16.5
- 14Poland58 cities15.7
- 15Italy42 cities13.8
- 16Czechia9 cities12.4
- 17North Macedonia15 cities12.4
- 18Slovakia41 cities12.2
- 19Hong Kong13 cities11.9
- 20Romania27 cities11.4
+ 29 more countries, 11.2 µg/m³ and below
- 40United States852 cities6.3
Not counted on this day, too few cities measured: Greece since 14 Apr 2026, Ghana since 8 Apr 2026, Bosnia and Herzegovina since 6 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.