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 19 Jan 2025: Pakistan 125.1 µg/m³, India 97.8 µg/m³ and Thailand 45.0 µg/m³.
- 1Pakistan4 cities125.1
- 2India5 cities97.8
- 3Thailand16 cities45.0
- 4China4 cities37.5
- 5Serbia10 cities35.7
- 6Bulgaria5 cities35.5
- 7Slovenia12 cities28.0
- 8Hong Kong13 cities27.2
- 9France10 cities, was 10526.5
- 10Hungary9 cities26.2
- 11Belgium44 cities25.2
- 12South Korea141 cities25.2
- 13Slovakia38 cities24.2
- 14Romania6 cities23.8
- 15Switzerland6 cities22.1
- 16Poland71 cities21.7
- 17The Netherlands22 cities19.8
- 18Mexico14 cities19.5
- 19Chile44 cities17.0
- 20Austria35 cities16.8
+ 15 more countries, 16.8 µg/m³ and below
- 28United States800 cities7.5
Not counted on this day, too few cities measured: Luxembourg since 18 Jan 2025, Estonia since 17 Jan 2025, Ireland since 17 Jan 2025 and 11 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.