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 22 Jan 2025: Pakistan 113.4 µg/m³, India 110.7 µg/m³ and Thailand 49.0 µg/m³.
- 1Pakistan4 cities113.4
- 2India5 cities110.7
- 3Thailand16 cities49.0
- 4Serbia10 cities43.8
- 5Bulgaria8 cities43.4
- 6China4 cities42.3
- 7Slovenia12 cities36.2
- 8South Korea141 cities36.0
- 9Poland72 cities34.3
- 10Romania9 cities34.2
- 11Hong Kong13 cities30.1
- 12Slovakia41 cities24.0
- 13Belgium45 cities23.9
- 14France80 cities, was 10523.6
- 15Hungary9 cities23.4
- 16The Netherlands22 cities21.6
- 17United Kingdom5 cities20.8
- 18Switzerland9 cities20.0
- 19Germany230 cities19.1
- 20Taiwan43 cities18.9
+ 17 more countries, 18.1 µg/m³ and below
- 30United States793 cities7.3
Not counted on this day, too few cities measured: Luxembourg since 21 Jan 2025, Estonia since 17 Jan 2025, Ireland since 17 Jan 2025 and 9 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.