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 17 Jan 2025: Pakistan 133.0 µg/m³, India 94.6 µg/m³ and China 44.0 µg/m³.
- 1Pakistan4 cities133.0
- 2India5 cities94.6
- 3China4 cities44.0
- 4Serbia24 cities40.0
- 5Thailand16 cities38.4
- 6Bulgaria5 cities26.2
- 7Hong Kong13 cities24.4
- 8Belgium44 cities24.1
- 9South Korea141 cities23.4
- 10Romania6 cities23.4
- 11Hungary8 cities22.6
- 12Slovenia12 cities22.6
- 13United Kingdom5 cities19.0
- 14Slovakia33 cities18.8
- 15France10 cities, was 10517.8
- 16Chile45 cities16.8
- 17The Netherlands22 cities16.7
- 18Switzerland6 cities16.5
- 19Mexico14 cities15.9
- 20Poland73 cities15.1
+ 16 more countries, 15.1 µg/m³ and below
- 29United States790 cities7.3
Not counted on this day, too few cities measured: Estonia since 17 Jan 2025, Ireland since 17 Jan 2025, Malta since 17 Jan 2025 and 10 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.