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 12 Mar 2025: India 46.7 µg/m³, Lithuania 44.6 µg/m³ and Serbia 40.9 µg/m³.
- 1India228 cities, was 546.7
- 2Lithuania4 cities44.6
- 3Serbia39 cities, was 1240.9
- 4Poland73 cities38.2
- 5Bosnia and Herzegovina4 cities31.9
- 6Romania11 cities31.4
- 7Croatia6 cities29.8
- 8South Korea140 cities26.1
- 9Latvia4 cities25.0
- 10United Kingdom7 cities24.8
- 11Thailand83 cities24.5
- 12Hungary12 cities23.9
- 13Germany250 cities23.4
- 14Belgium45 cities23.1
- 15Slovakia42 cities22.6
- 16Kosovo7 cities20.0
- 17The Netherlands30 cities19.7
- 18Mexico10 cities18.7
- 19Slovenia12 cities18.4
- 20Peru6 cities18.1
+ 24 more countries, 18.0 µg/m³ and below
- 36United States827 cities5.4
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 Czechia since 25 Feb 2025.
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.