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 14 Sep 2024: Pakistan 44.5 µg/m³, Peru 28.9 µg/m³ and Chile 26.7 µg/m³.
- 1Pakistan4 cities44.5
- 2Peru15 cities28.9
- 3Chile45 cities26.7
- 4China3 cities23.8
- 5India5 cities21.2
- 6Hungary4 cities15.4
- 7Thailand18 cities15.4
- 8Hong Kong13 cities11.7
- 9South Korea140 cities11.6
- 10Singapore5 cities11.5
- 11Taiwan43 cities11.2
- 12Serbia10 cities10.9
- 13Poland73 cities10.0
- 14Japan537 cities8.1
- 15Australia35 cities6.8
- 16United States801 cities6.7
- 17Canada117 cities6.6
- 18Norway17 cities6.1
- 19Bulgaria5 cities5.5
- 20New Zealand5 cities5.3
+ 3 more countries, 5.0 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.