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 1 Sep 2024: Chile 37.2 µg/m³, Pakistan 34.9 µg/m³ and China 22.5 µg/m³.
- 1Chile45 cities37.2
- 2Pakistan4 cities34.9
- 3China3 cities22.5
- 4Peru15 cities20.5
- 5Hungary5 cities16.3
- 6Singapore5 cities14.7
- 7Taiwan43 cities14.2
- 8Poland71 cities13.4
- 9Hong Kong13 cities13.3
- 10India5 cities12.2
- 11South Korea141 cities11.7
- 12Thailand14 cities, was 911.5
- 13The Netherlands20 cities9.6
- 14United Kingdom62 cities9.4
- 15Mexico4 cities9.4
- 16Bulgaria5 cities8.5
- 17United States810 cities7.4
- 18Norway17 cities6.6
- 19Canada119 cities6.0
- 20Australia34 cities5.9
+ 2 more countries, 4.7 µg/m³ and below
Not counted on this day, too few cities measured: Serbia since 1 Sep 2024, Iceland since 30 Aug 2024, Belgium since 17 Aug 2024 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.