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 13 Sep 2024: Pakistan 43.1 µg/m³, Peru 27.9 µg/m³ and Chile 26.3 µg/m³.
- 1Pakistan4 cities43.1
- 2Peru15 cities27.9
- 3Chile45 cities26.3
- 4China3 cities23.5
- 5India5 cities22.0
- 6Hungary4 cities16.5
- 7Thailand17 cities15.3
- 8Serbia10 cities12.3
- 9South Korea140 cities12.1
- 10Singapore5 cities11.8
- 11Poland72 cities11.5
- 12Taiwan43 cities11.1
- 13Hong Kong13 cities11.0
- 14Japan540 cities9.6
- 15Norway17 cities7.5
- 16Australia35 cities6.9
- 17United States794 cities6.6
- 18United Kingdom62 cities6.1
- 19Bulgaria5 cities6.0
- 20Canada113 cities6.0
+ 3 more countries, 5.3 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 12 Sep 2024, Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024 and 22 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.