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 26 May 2023: China 50.4 µg/m³, Pakistan 37.1 µg/m³ and South Africa 34.8 µg/m³.
- 1China3 cities50.4
- 2Pakistan4 cities37.1
- 3South Africa6 cities34.8
- 4India5 cities29.1
- 5Chile45 cities27.9
- 6Thailand18 cities, was 7726.7
- 7Mexico13 cities, was 4718.8
- 8Serbia3 cities, was 2115.3
- 9Luxembourg3 cities13.9
- 10Slovakia26 cities13.9
- 11Hong Kong13 cities13.8
- 12Poland66 cities13.2
- 13Czechia34 cities13.1
- 14Belgium41 cities12.4
- 15Greece7 cities12.0
- 16Germany194 cities11.5
- 17Austria30 cities11.4
- 18Italy24 cities10.9
- 19Lithuania3 cities10.9
- 20Hungary8 cities10.8
+ 18 more countries, 10.7 µg/m³ and below
- 29United States731 cities9.1
Not counted on this day, too few cities measured: Kosovo since 24 May 2023, Martinique since 20 May 2023, Laos since 10 May 2023 and 2 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.