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 6 Oct 2025: Pakistan 56.6 µg/m³, Peru 33.4 µg/m³ and India 23.0 µg/m³.
- 1Pakistan11 cities56.6
- 2Peru5 cities33.4
- 3India209 cities23.0
- 4Chile46 cities22.8
- 5Philippines3 cities20.0
- 6Ghana4 cities19.3
- 7Serbia36 cities12.6
- 8Mexico46 cities11.2
- 9Bosnia and Herzegovina5 cities11.0
- 10Thailand75 cities10.2
- 11Taiwan45 cities10.1
- 12Poland72 cities9.4
- 13Italy24 cities9.2
- 14Brazil3 cities9.0
- 15South Korea141 cities8.7
- 16Romania11 cities8.6
- 17Greece5 cities8.3
- 18Hungary9 cities8.3
- 19Latvia4 cities8.3
- 20Spain111 cities7.9
+ 28 more countries, 7.7 µg/m³ and below
- 28United States875 cities6.9
Not counted on this day, too few cities measured: Czechia since 18 Sep 2025 and Luxembourg since 2 Sep 2025.
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.