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 13 Jan 2025: Pakistan 116.4 µg/m³, India 90.9 µg/m³ and Thailand 43.9 µg/m³.
- 1Pakistan4 cities116.4
- 2India5 cities90.9
- 3Thailand16 cities43.9
- 4China4 cities43.2
- 5Romania10 cities31.8
- 6Serbia24 cities31.4
- 7Hong Kong13 cities26.2
- 8Bulgaria5 cities25.7
- 9Greece6 cities22.1
- 10United Kingdom5 cities18.5
- 11Ireland7 cities17.3
- 12South Korea141 cities17.3
- 13Chile44 cities16.8
- 14Mexico15 cities15.1
- 15Taiwan43 cities13.4
- 16Peru5 cities, was 1613.3
- 17Slovenia12 cities12.7
- 18Belgium45 cities12.6
- 19Poland73 cities11.8
- 20Hungary9 cities11.0
+ 21 more countries, 10.6 µg/m³ and below
- 29United States798 cities7.1
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.