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 Feb 2025: India 81.2 µg/m³, Pakistan 71.9 µg/m³ and Bosnia and Herzegovina 47.0 µg/m³.
- 1India5 cities81.2
- 2Pakistan4 cities71.9
- 3Bosnia and Herzegovina4 cities47.0
- 4Thailand84 cities, was 1641.3
- 5Serbia39 cities36.9
- 6China3 cities36.4
- 7Poland76 cities36.4
- 8Laos3 cities31.9
- 9Hong Kong11 cities28.3
- 10Romania10 cities27.6
- 11Slovenia12 cities26.3
- 12Bulgaria8 cities26.0
- 13Czechia37 cities, was 3725.5
- 14Belgium45 cities25.4
- 15Hungary12 cities24.9
- 16The Netherlands24 cities24.2
- 17United Kingdom5 cities22.4
- 18France104 cities22.1
- 19South Korea141 cities21.9
- 20Slovakia39 cities21.9
+ 23 more countries, 21.3 µg/m³ and below
- 35United States823 cities6.5
Not counted on this day, too few cities measured: Ireland since 16 Feb 2025, Lithuania since 16 Feb 2025, Martinique since 15 Feb 2025 and 2 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.