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 17 Sep 2023: Pakistan 43.4 µg/m³, Peru 28.3 µg/m³ and China 24.7 µg/m³.
- 1Pakistan4 cities43.4
- 2Peru4 cities28.3
- 3China3 cities24.7
- 4Chile43 cities22.6
- 5India5 cities18.7
- 6Singapore5 cities16.2
- 7Mexico41 cities15.4
- 8Malta4 cities14.6
- 9Poland62 cities14.2
- 10Czechia36 cities13.9
- 11Serbia3 cities13.8
- 12Italy30 cities13.2
- 13Hungary9 cities12.5
- 14Greece7 cities12.4
- 15Slovakia27 cities12.1
- 16Bulgaria6 cities11.2
- 17Thailand10 cities11.1
- 18Austria30 cities10.6
- 19Belgium41 cities10.5
- 20Germany61 cities10.3
+ 16 more countries, 9.4 µg/m³ and below
- 31United States751 cities6.7
Not counted on this day, too few cities measured: North Macedonia since 16 Sep 2023, Lithuania since 11 Sep 2023 and Luxembourg since 6 Sep 2023.
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.