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 28 Aug 2023: Pakistan 38.2 µg/m³, Chile 34.8 µg/m³ and India 27.7 µg/m³.
- 1Pakistan4 cities38.2
- 2Chile44 cities34.8
- 3India5 cities27.7
- 4Peru3 cities25.3
- 5China3 cities22.8
- 6Malta4 cities15.7
- 7Thailand11 cities14.1
- 8Mexico36 cities, was 1113.9
- 9Greece7 cities12.8
- 10Serbia3 cities12.2
- 11Singapore5 cities12.0
- 12Slovakia27 cities10.9
- 13Czechia28 cities10.7
- 14Canada113 cities10.6
- 15Italy9 cities10.5
- 16Romania6 cities10.5
- 17North Macedonia7 cities10.2
- 18Hungary7 cities10.1
- 19Bulgaria6 cities10.0
- 20United States759 cities9.3
+ 14 more countries, 9.2 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 22 Aug 2023, Poland since 21 Aug 2023, Reunion since 16 Aug 2023 and 2 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.