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 19 Feb 2025: India 77.7 µg/m³, Pakistan 69.6 µg/m³ and Serbia 38.4 µg/m³.
- 1India5 cities77.7
- 2Pakistan4 cities69.6
- 3Serbia39 cities38.4
- 4Thailand85 cities, was 1637.9
- 5Poland76 cities37.0
- 6China3 cities34.8
- 7Bosnia and Herzegovina4 cities34.7
- 8Laos3 cities30.0
- 9Hong Kong11 cities29.1
- 10Romania10 cities25.8
- 11Belgium45 cities25.7
- 12Czechia37 cities, was 3725.5
- 13Hungary12 cities25.4
- 14United Kingdom6 cities25.0
- 15Slovenia12 cities24.6
- 16Bulgaria8 cities24.0
- 17The Netherlands24 cities23.3
- 18Slovakia40 cities22.5
- 19Switzerland10 cities, was 1022.3
- 20France109 cities22.2
+ 26 more countries, the next at 20.6 µg/m³
- 39United States819 cities6.2
Not counted on this day, too few cities measured: Lithuania since 16 Feb 2025, Martinique since 15 Feb 2025 and Singapore since 9 Jan 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.