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 24 Sep 2024: Pakistan 72.9 µg/m³, India 35.7 µg/m³ and Chile 22.3 µg/m³.
- 1Pakistan3 cities72.9
- 2India5 cities35.7
- 3Chile46 cities22.3
- 4Peru16 cities22.0
- 5Poland73 cities21.1
- 6Singapore5 cities18.0
- 7Serbia23 cities17.4
- 8Hungary4 cities16.9
- 9China3 cities15.8
- 10Thailand18 cities, was 6614.5
- 11The Netherlands22 cities13.8
- 12United Kingdom63 cities13.4
- 13Norway18 cities9.0
- 14Hong Kong10 cities8.0
- 15Australia35 cities7.3
- 16Bulgaria5 cities7.3
- 17Taiwan43 cities6.6
- 18New Zealand5 cities6.2
- 19Japan520 cities6.1
- 20United States821 cities6.0
+ 3 more countries, 5.4 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 19 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.