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 Sep 2024: Pakistan 67.6 µg/m³, India 29.4 µg/m³ and Chile 27.5 µg/m³.
- 1Pakistan3 cities67.6
- 2India5 cities29.4
- 3Chile45 cities27.5
- 4Peru16 cities22.4
- 5China3 cities19.2
- 6Poland72 cities18.0
- 7Singapore5 cities16.8
- 8Thailand19 cities15.5
- 9Hong Kong13 cities12.5
- 10The Netherlands22 cities12.2
- 11Serbia24 cities11.4
- 12Hungary4 cities10.7
- 13Taiwan43 cities8.7
- 14United Kingdom62 cities8.3
- 15South Korea141 cities6.9
- 16Japan518 cities6.6
- 17Canada120 cities6.5
- 18United States813 cities6.3
- 19New Zealand5 cities6.1
- 20Australia35 cities6.0
+ 3 more countries, 5.1 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 19 Sep 2024, Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024 and 22 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.