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 19 Jul 2023: Chile 49.3 µg/m³, Pakistan 41.3 µg/m³ and China 23.1 µg/m³.
- 1Chile45 cities49.3
- 2Pakistan4 cities41.3
- 3China3 cities23.1
- 4Greece7 cities15.8
- 5Mexico13 cities15.4
- 6India5 cities13.5
- 7Romania4 cities12.8
- 8North Macedonia7 cities12.5
- 9Slovakia19 cities12.3
- 10Thailand11 cities11.7
- 11United States724 cities11.7
- 12Canada104 cities10.9
- 13Bulgaria3 cities10.7
- 14Spain67 cities10.0
- 15Singapore5 cities9.9
- 16Czechia24 cities9.7
- 17Germany40 cities, was 1946.4
- 18France90 cities6.4
- 19Austria15 cities6.1
- 20Belgium27 cities5.2
+ 5 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 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.