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 30 days to 19 Feb 2025: India 84.3 µg/m³, Pakistan 76.6 µg/m³ and Bosnia and Herzegovina 57.8 µg/m³.
- 1India5 cities84.3
- 2Pakistan4 cities76.6
- 3Bosnia and Herzegovina4 cities57.8
- 4Thailand78 cities, was 1642.4
- 5Serbia25 cities41.5
- 6China4 cities34.6
- 7Poland76 cities29.6
- 8Slovenia12 cities27.8
- 9Romania8 cities27.5
- 10Bulgaria5 cities24.4
- 11Czechia19 cities, was 3623.4
- 12Hungary11 cities22.1
- 13Slovakia42 cities22.0
- 14South Korea141 cities20.6
- 15Chile45 cities19.7
- 16Croatia3 cities19.5
- 17Belgium45 cities19.1
- 18Hong Kong13 cities19.1
- 19The Netherlands23 cities19.1
- 20Austria36 cities18.4
+ 26 more countries, the next at 17.5 µg/m³
- 38United States824 cities7.2
Not counted on this day, too few cities measured: Luxembourg since 2 Feb 2025 and Singapore since 16 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.