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 17 Apr 2026: Laos 171.7 µg/m³, India 39.4 µg/m³ and Pakistan 37.6 µg/m³.
- 1Laos3 cities171.7
- 2India228 cities39.4
- 3Pakistan13 cities37.6
- 4Thailand82 cities31.9
- 5Malta5 cities30.3
- 6Czechia3 cities29.8
- 7Chile45 cities27.7
- 8Peru6 cities24.2
- 9Serbia8 cities19.9
- 10Mexico48 cities18.9
- 11Senegal4 cities18.0
- 12South Korea140 cities17.5
- 13Taiwan43 cities17.3
- 14Hungary13 cities16.4
- 15Kazakhstan4 cities16.2
- 16Slovakia42 cities16.0
- 17North Macedonia15 cities15.7
- 18Italy40 cities14.6
- 19Malawi5 cities14.3
- 20Slovenia12 cities14.3
+ 28 more countries, 13.8 µg/m³ and below
- 39United States850 cities6.2
Not counted on this day, too few cities measured: Poland since 16 Apr 2026, Greece since 14 Apr 2026, Ghana since 8 Apr 2026 and 3 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.