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 Sep 2024: Pakistan 72.9 µg/m³, India 28.4 µg/m³ and Chile 26.5 µg/m³.
- 1Pakistan3 cities72.9
- 2India5 cities28.4
- 3Chile45 cities26.5
- 4Peru16 cities22.4
- 5Poland73 cities20.8
- 6Singapore5 cities17.3
- 7China3 cities16.9
- 8Thailand19 cities, was 6615.8
- 9The Netherlands22 cities13.2
- 10Serbia24 cities12.9
- 11Hungary4 cities12.0
- 12Hong Kong13 cities11.6
- 13United Kingdom62 cities10.2
- 14Taiwan43 cities8.2
- 15Japan518 cities6.6
- 16Australia35 cities6.4
- 17New Zealand5 cities6.4
- 18United States815 cities6.2
- 19South Korea141 cities6.1
- 20Canada120 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.