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 24 Sep 2024: Pakistan 56.7 µg/m³, Chile 28.4 µg/m³ and Peru 27.3 µg/m³.
- 1Pakistan3 cities56.7
- 2Chile45 cities28.4
- 3Peru15 cities27.3
- 4India5 cities20.7
- 5China3 cities20.6
- 6Hungary4 cities17.2
- 7Poland73 cities16.0
- 8Singapore5 cities15.6
- 9Serbia10 cities15.1
- 10Thailand16 cities13.1
- 11Hong Kong13 cities12.0
- 12Taiwan43 cities11.1
- 13South Korea141 cities9.6
- 14The Netherlands20 cities9.3
- 15United Kingdom64 cities8.9
- 16Mexico3 cities8.0
- 17Bulgaria5 cities7.3
- 18Japan544 cities7.2
- 19Norway18 cities7.0
- 20Australia35 cities6.9
+ 4 more countries, 6.8 µg/m³ and below
- 21United States815 cities6.8
Not counted on this day, too few cities measured: Belgium since 24 Aug 2024, Switzerland since 24 Aug 2024, Germany since 24 Aug 2024 and 19 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.