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 31 Jan 2023: India 95.0 µg/m³, Pakistan 89.6 µg/m³ and Thailand 38.0 µg/m³.
- 1India3 cities95.0
- 2Pakistan4 cities89.6
- 3Thailand69 cities38.0
- 4China3 cities33.4
- 5Hong Kong12 cities24.9
- 6Mexico47 cities24.1
- 7Hungary7 cities19.0
- 8Poland70 cities18.8
- 9Slovakia25 cities18.4
- 10Bulgaria7 cities17.8
- 11Chile42 cities17.8
- 12Kosovo6 cities16.8
- 13Romania7 cities16.1
- 14Peru5 cities15.9
- 15France69 cities15.5
- 16Greece9 cities15.0
- 17Italy17 cities14.9
- 18South Africa8 cities13.8
- 19Czechia30 cities13.6
- 20The Netherlands29 cities13.2
+ 13 more countries, the next at 9.9 µg/m³
- 26United States677 cities7.1
Not counted on this day, too few cities measured: Austria since 19 Jan 2023, Belgium since 19 Jan 2023, Germany since 19 Jan 2023 and 7 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, 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.