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 10 Dec 2024: Pakistan 100.4 µg/m³, India 64.3 µg/m³ and Bosnia and Herzegovina 37.5 µg/m³.
- 1Pakistan3 cities100.4
- 2India5 cities64.3
- 3Bosnia and Herzegovina4 cities37.5
- 4China4 cities36.6
- 5Serbia23 cities34.5
- 6Thailand16 cities31.0
- 7Hong Kong13 cities26.2
- 8Slovenia12 cities25.3
- 9Poland76 cities20.3
- 10Hungary10 cities19.9
- 11Peru18 cities19.8
- 12Bulgaria8 cities19.4
- 13Croatia6 cities19.4
- 14Chile46 cities18.6
- 15Mexico11 cities18.0
- 16Greece9 cities16.9
- 17Slovakia39 cities13.6
- 18South Korea140 cities13.0
- 19Latvia4 cities11.7
- 20Taiwan43 cities11.5
+ 25 more countries, 11.3 µg/m³ and below
- 26United States811 cities7.3
Not counted on this day, too few cities measured: Lithuania since 7 Dec 2024, Puerto Rico since 7 Dec 2024, Luxembourg since 1 Dec 2024 and 2 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.