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 19 Sep 2024: Pakistan 64.7 µg/m³, Chile 26.7 µg/m³ and India 25.8 µg/m³.
- 1Pakistan3 cities64.7
- 2Chile45 cities26.7
- 3India5 cities25.8
- 4Peru16 cities25.6
- 5China3 cities20.9
- 6Poland72 cities16.2
- 7Thailand19 cities15.9
- 8Singapore5 cities14.8
- 9Hong Kong13 cities12.8
- 10Hungary4 cities11.2
- 11The Netherlands20 cities10.6
- 12Serbia24 cities10.4
- 13Taiwan43 cities8.9
- 14South Korea141 cities7.4
- 15Canada120 cities7.1
- 16Japan523 cities6.5
- 17United States808 cities6.4
- 18United Kingdom61 cities6.2
- 19New Zealand5 cities6.1
- 20Australia35 cities5.5
+ 3 more countries, 4.8 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.