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 18 Jul 2023: Chile 53.9 µg/m³, Pakistan 30.8 µg/m³ and China 21.1 µg/m³.
- 1Chile43 cities53.9
- 2Pakistan3 cities30.8
- 3China3 cities21.1
- 4Greece7 cities16.4
- 5India5 cities16.0
- 6Mexico12 cities13.9
- 7Romania4 cities13.3
- 8Slovakia19 cities12.4
- 9Thailand11 cities12.3
- 10North Macedonia7 cities12.2
- 11United States727 cities11.2
- 12Bulgaria3 cities11.0
- 13Canada102 cities10.8
- 14Czechia25 cities10.0
- 15Spain67 cities9.8
- 16Singapore5 cities9.5
- 17France91 cities6.3
- 18Germany39 cities, was 1946.2
- 19Austria15 cities5.9
- 20United Kingdom3 cities, was 55.3
+ 5 more countries, 5.0 µg/m³ and below
Not counted on this day, too few cities measured: Switzerland since 16 Jul 2023, Hungary since 16 Jul 2023, Ireland since 16 Jul 2023 and 14 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.