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 30 days to 28 Jun 2023: Chile 42.8 µg/m³, Pakistan 40.9 µg/m³ and India 32.1 µg/m³.
- 1Chile46 cities42.8
- 2Pakistan4 cities40.9
- 3India5 cities32.1
- 4China3 cities24.3
- 5Mexico12 cities18.7
- 6Thailand11 cities13.6
- 7Malta4 cities12.8
- 8Serbia3 cities12.0
- 9Greece8 cities11.5
- 10Czechia36 cities11.4
- 11Slovakia27 cities10.9
- 12Belgium41 cities10.6
- 13United States743 cities10.6
- 14Italy26 cities10.1
- 15Hungary8 cities9.8
- 16Martinique3 cities9.8
- 17Canada106 cities9.7
- 18Germany197 cities9.6
- 19Switzerland9 cities9.4
- 20Lithuania4 cities9.4
+ 11 more countries, 9.3 µg/m³ and below
Not counted on this day, too few cities measured: Romania since 7 Jun 2023, Poland since 29 May 2023, Luxembourg since 27 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.