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 Jan 2023: India 100.1 µg/m³, Pakistan 86.9 µg/m³ and Thailand 35.9 µg/m³.
- 1India3 cities100.1
- 2Pakistan3 cities86.9
- 3Thailand63 cities35.9
- 4China3 cities31.2
- 5Hong Kong11 cities25.0
- 6Mexico45 cities23.2
- 7Poland69 cities20.5
- 8Hungary6 cities18.5
- 9Chile43 cities17.5
- 10The Netherlands29 cities17.5
- 11France67 cities17.4
- 12Greece9 cities16.9
- 13South Africa3 cities16.7
- 14Peru5 cities16.3
- 15Czechia30 cities16.1
- 16Slovakia25 cities15.8
- 17United Kingdom43 cities15.0
- 18Bulgaria7 cities13.2
- 19Italy15 cities13.1
- 20Norway20 cities10.9
+ 12 more countries, 10.6 µg/m³ and below
- 25United States672 cities7.1
Not counted on this day, too few cities measured: Kosovo since 20 Jan 2023, Austria since 19 Jan 2023, Belgium since 19 Jan 2023 and 8 more countries. Days missing from the source archive fall in this window, so fewer countries are counted.
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.