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 15 Sep 2024: Pakistan 56.4 µg/m³, Peru 28.8 µg/m³ and Chile 26.7 µg/m³.
- 1Pakistan3 cities56.4
- 2Peru15 cities28.8
- 3Chile45 cities26.7
- 4China3 cities23.4
- 5India5 cities21.2
- 6Thailand17 cities14.8
- 7Hong Kong13 cities14.4
- 8Hungary4 cities13.7
- 9Singapore5 cities11.8
- 10Taiwan43 cities11.3
- 11South Korea140 cities10.8
- 12Serbia10 cities9.6
- 13Poland72 cities8.9
- 14Canada119 cities7.0
- 15United States797 cities6.8
- 16Japan533 cities6.7
- 17Australia35 cities6.5
- 18Bulgaria5 cities5.8
- 19The Netherlands20 cities5.7
- 20New Zealand5 cities5.2
+ 3 more countries, 4.6 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.