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 30 Jan 2023: Pakistan 92.6 µg/m³, India 91.5 µg/m³ and Thailand 37.6 µg/m³.
- 1Pakistan4 cities92.6
- 2India3 cities91.5
- 3Thailand69 cities37.6
- 4China3 cities32.7
- 5Hong Kong12 cities25.0
- 6Mexico48 cities24.3
- 7Poland70 cities20.5
- 8Hungary7 cities18.7
- 9Slovakia25 cities18.5
- 10Chile42 cities17.9
- 11Kosovo6 cities17.5
- 12Italy15 cities17.2
- 13Bulgaria7 cities17.1
- 14France68 cities16.9
- 15Peru5 cities15.9
- 16Greece10 cities15.6
- 17The Netherlands29 cities14.6
- 18South Africa8 cities14.6
- 19Czechia30 cities14.2
- 20Romania7 cities13.2
+ 13 more countries, 11.5 µg/m³ and below
- 26United States675 cities7.2
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 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.