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 9 Mar 2025: Serbia 50.0 µg/m³, Bosnia and Herzegovina 46.3 µg/m³ and India 41.4 µg/m³.
- 1Serbia39 cities, was 1250.0
- 2Bosnia and Herzegovina4 cities46.3
- 3India227 cities, was 541.4
- 4Croatia5 cities37.3
- 5Poland72 cities33.2
- 6Romania11 cities31.6
- 7Switzerland3 cities27.8
- 8The Netherlands36 cities26.6
- 9United Kingdom7 cities26.5
- 10Slovakia39 cities26.3
- 11Hungary12 cities25.4
- 12Latvia4 cities23.0
- 13Belgium44 cities22.4
- 14Slovenia12 cities22.1
- 15Germany246 cities21.5
- 16Thailand85 cities21.2
- 17Peru6 cities18.6
- 18Mexico8 cities18.5
- 19Chile44 cities17.6
- 20Bulgaria8 cities17.5
+ 22 more countries, 17.0 µg/m³ and below
- 35United States835 cities5.7
Not counted on this day, too few cities measured: China since 7 Mar 2025, Laos since 7 Mar 2025, Pakistan since 6 Mar 2025 and 3 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.