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 18 Oct 2024: Pakistan 78.4 µg/m³, China 26.4 µg/m³ and India 26.4 µg/m³.
- 1Pakistan3 cities78.4
- 2China3 cities26.4
- 3India5 cities26.4
- 4Chile46 cities21.4
- 5Peru16 cities21.1
- 6Thailand16 cities17.6
- 7Hong Kong13 cities15.2
- 8Serbia24 cities15.2
- 9Hungary4 cities13.4
- 10Singapore5 cities13.3
- 11Poland72 cities12.5
- 12South Korea141 cities9.7
- 13Taiwan43 cities9.1
- 14United Kingdom63 cities7.4
- 15The Netherlands22 cities6.9
- 16Japan550 cities6.8
- 17Australia35 cities6.6
- 18Bulgaria5 cities6.5
- 19United States807 cities6.3
- 20Norway17 cities6.2
+ 3 more countries, 5.5 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 15 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.