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 23 Nov 2025: Pakistan 205.0 µg/m³, India 67.3 µg/m³ and Bosnia and Herzegovina 26.4 µg/m³.
- 1Pakistan12 cities205.0
- 2India240 cities67.3
- 3Bosnia and Herzegovina5 cities26.4
- 4Mexico49 cities24.2
- 5Ghana4 cities23.9
- 6Peru4 cities23.6
- 7Serbia30 cities23.1
- 8North Macedonia12 cities20.0
- 9Hong Kong13 cities19.4
- 10Poland65 cities18.9
- 11Chile41 cities18.0
- 12South Korea137 cities16.9
- 13Thailand68 cities16.6
- 14Taiwan44 cities14.2
- 15Hungary13 cities12.8
- 16Montenegro5 cities12.3
- 17Slovakia42 cities12.2
- 18Latvia4 cities11.3
- 19Philippines3 cities10.9
- 20Kosovo8 cities10.6
+ 24 more countries, 10.0 µg/m³ and below
- 32United States271 cities, was 8697.5
Not counted on this day, too few cities measured: Czechia since 23 Nov 2025, Martinique since 21 Nov 2025, Romania since 17 Nov 2025 and 4 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.