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 10 Dec 2024: Pakistan 108.8 µg/m³, India 77.3 µg/m³ and Bosnia and Herzegovina 65.6 µg/m³.
- 1Pakistan3 cities108.8
- 2India5 cities77.3
- 3Bosnia and Herzegovina4 cities65.6
- 4Serbia25 cities37.5
- 5China3 cities34.3
- 6Thailand16 cities28.3
- 7Slovenia11 cities21.8
- 8Hungary11 cities20.6
- 9Romania9 cities20.6
- 10Croatia5 cities19.5
- 11Poland75 cities19.5
- 12Peru15 cities19.4
- 13Hong Kong13 cities19.1
- 14Bulgaria8 cities18.4
- 15Chile46 cities18.2
- 16Slovakia37 cities18.0
- 17Mexico11 cities17.5
- 18South Korea141 cities14.5
- 19Czechia36 cities12.8
- 20Taiwan43 cities12.5
+ 24 more countries, 10.7 µg/m³ and below
- 35United States827 cities6.7
Not counted on this day, too few cities measured: Luxembourg since 7 Dec 2024 and Lithuania since 4 Dec 2024.
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.