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 20 Oct 2024: Pakistan 81.7 µg/m³, China 27.1 µg/m³ and India 26.3 µg/m³.
- 1Pakistan3 cities81.7
- 2China3 cities27.1
- 3India5 cities26.3
- 4Chile46 cities21.3
- 5Peru16 cities20.9
- 6Thailand16 cities17.3
- 7Hong Kong13 cities15.4
- 8Serbia21 cities14.8
- 9Hungary4 cities14.2
- 10Singapore5 cities13.2
- 11Poland72 cities12.4
- 12South Korea140 cities9.6
- 13Taiwan43 cities9.4
- 14Australia35 cities6.6
- 15Japan551 cities6.6
- 16Bulgaria5 cities6.5
- 17United Kingdom63 cities6.5
- 18Norway17 cities6.5
- 19United States805 cities6.5
- 20The Netherlands22 cities6.3
+ 3 more countries, 5.6 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 26 Sep 2024, Belgium since 24 Aug 2024, Switzerland since 24 Aug 2024 and 14 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.