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 27 May 2024: Chile 43.2 µg/m³, Pakistan 36.9 µg/m³ and India 34.9 µg/m³.
- 1Chile45 cities43.2
- 2Pakistan4 cities36.9
- 3India4 cities34.9
- 4Laos3 cities31.3
- 5China3 cities25.0
- 6Mexico9 cities24.1
- 7Thailand81 cities, was 1522.8
- 8Peru12 cities22.6
- 9Malta5 cities14.9
- 10South Korea141 cities14.7
- 11Taiwan43 cities14.7
- 12New Zealand5 cities13.2
- 13Hong Kong10 cities12.6
- 14Belgium44 cities11.3
- 15The Netherlands36 cities10.7
- 16Greece7 cities10.6
- 17Serbia24 cities10.3
- 18Latvia4 cities10.0
- 19Poland77 cities9.9
- 20Singapore5 cities9.6
+ 27 more countries, 9.3 µg/m³ and below
- 37United States808 cities6.3
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 2 May 2024.
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.