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 15 Jan 2025: Pakistan 124.4 µg/m³, India 92.2 µg/m³ and Thailand 42.7 µg/m³.
- 1Pakistan4 cities124.4
- 2India5 cities92.2
- 3Thailand16 cities42.7
- 4China4 cities40.8
- 5Serbia25 cities35.8
- 6Romania10 cities26.2
- 7Hong Kong13 cities22.8
- 8Bulgaria5 cities21.3
- 9United Kingdom5 cities20.6
- 10South Korea141 cities20.5
- 11Belgium45 cities20.2
- 12Greece3 cities, was 919.4
- 13Slovenia12 cities17.9
- 14Chile43 cities17.6
- 15Ireland7 cities15.6
- 16Taiwan43 cities15.6
- 17Hungary9 cities14.3
- 18France21 cities, was 10514.1
- 19Peru5 cities, was 1613.9
- 20Mexico15 cities13.8
+ 21 more countries, 13.5 µg/m³ and below
- 32United States795 cities7.3
Not counted on this day, too few cities measured: Lithuania since 13 Jan 2025, Czechia since 11 Jan 2025, Croatia since 11 Jan 2025 and 5 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.