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 20 Jul 2023: Chile 52.2 µg/m³, Pakistan 37.7 µg/m³ and China 26.9 µg/m³.
- 1Chile45 cities52.2
- 2Pakistan4 cities37.7
- 3China3 cities26.9
- 4Martinique3 cities18.0
- 5Greece7 cities14.7
- 6Mexico21 cities14.4
- 7North Macedonia7 cities13.4
- 8Slovakia19 cities12.6
- 9Thailand11 cities12.4
- 10United States726 cities12.2
- 11Romania4 cities12.0
- 12India5 cities11.7
- 13Canada105 cities11.5
- 14Spain64 cities11.1
- 15Singapore5 cities10.3
- 16Bulgaria3 cities10.1
- 17Czechia24 cities9.2
- 18France91 cities6.4
- 19Germany40 cities, was 1946.3
- 20Austria15 cities6.1
+ 6 more countries, 5.2 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 13 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.