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 25 Aug 2024: Chile 39.6 µg/m³, Pakistan 32.0 µg/m³ and China 22.3 µg/m³.
- 1Chile44 cities39.6
- 2Pakistan4 cities32.0
- 3China4 cities22.3
- 4Peru16 cities20.6
- 5India5 cities17.5
- 6New Zealand5 cities13.2
- 7Thailand17 cities13.1
- 8Singapore5 cities12.9
- 9South Korea140 cities11.3
- 10Hong Kong13 cities10.2
- 11Hungary5 cities10.2
- 12Serbia12 cities10.1
- 13Poland71 cities9.4
- 14Canada117 cities8.8
- 15Japan553 cities8.8
- 16Mexico3 cities8.7
- 17United States804 cities8.7
- 18Taiwan43 cities8.6
- 19The Netherlands20 cities6.7
- 20Australia34 cities6.0
+ 4 more countries, 5.7 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 24 Aug 2024, Switzerland since 24 Aug 2024, Germany since 24 Aug 2024 and 21 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.