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 27 Aug 2023: Pakistan 40.8 µg/m³, India 26.3 µg/m³ and Chile 26.1 µg/m³.
- 1Pakistan4 cities40.8
- 2India5 cities26.3
- 3Chile42 cities26.1
- 4China3 cities16.1
- 5Thailand11 cities12.9
- 6Bulgaria4 cities11.7
- 7Singapore5 cities11.3
- 8Mexico13 cities11.0
- 9United States759 cities10.3
- 10Canada116 cities10.1
- 11Japan517 cities6.1
- 12United Kingdom3 cities, was 45.1
Not counted on this day, too few cities measured: Austria since 27 Aug 2023, Belgium since 27 Aug 2023, Switzerland since 27 Aug 2023 and 24 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.