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 21 Aug 2024: Chile 40.8 µg/m³, Pakistan 29.4 µg/m³ and Peru 22.8 µg/m³.
- 1Chile44 cities40.8
- 2Pakistan4 cities29.4
- 3Peru14 cities22.8
- 4India5 cities18.9
- 5China4 cities16.8
- 6Serbia10 cities14.2
- 7Hungary5 cities13.3
- 8Thailand17 cities, was 912.2
- 9Singapore5 cities11.9
- 10New Zealand5 cities11.8
- 11Poland69 cities11.4
- 12South Korea140 cities9.2
- 13Canada116 cities8.4
- 14Hong Kong11 cities8.2
- 15Japan559 cities8.1
- 16United States799 cities8.1
- 17United Kingdom63 cities6.8
- 18The Netherlands20 cities6.8
- 19Mexico3 cities6.4
- 20Bulgaria5 cities5.9
+ 4 more countries, 5.4 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024, Germany 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.