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 18 Jan 2025: Pakistan 132.4 µg/m³, India 96.1 µg/m³ and Thailand 41.5 µg/m³.
- 1Pakistan4 cities132.4
- 2India5 cities96.1
- 3Thailand16 cities41.5
- 4China4 cities41.0
- 5Serbia15 cities37.0
- 6Bulgaria5 cities31.2
- 7South Korea141 cities25.3
- 8Hong Kong13 cities25.0
- 9Hungary8 cities24.8
- 10Slovenia12 cities24.6
- 11Romania6 cities24.4
- 12Belgium44 cities23.4
- 13Slovakia34 cities21.9
- 14France10 cities, was 10521.5
- 15Switzerland6 cities19.2
- 16Mexico14 cities18.2
- 17Poland73 cities18.1
- 18The Netherlands22 cities16.8
- 19Chile45 cities16.7
- 20United Kingdom5 cities16.3
+ 15 more countries, 16.2 µg/m³ and below
- 28United States801 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.