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 25 Mar 2026: Laos 52.4 µg/m³, Kazakhstan 52.0 µg/m³ and Pakistan 42.5 µg/m³.
- 1Laos3 cities52.4
- 2Kazakhstan4 cities52.0
- 3Pakistan12 cities42.5
- 4India235 cities33.3
- 5South Korea141 cities28.6
- 6Poland59 cities27.3
- 7Thailand81 cities25.5
- 8Peru5 cities25.0
- 9Serbia4 cities23.2
- 10Latvia4 cities22.2
- 11Belgium52 cities20.3
- 12Bosnia and Herzegovina6 cities20.2
- 13France111 cities19.4
- 14Ghana3 cities19.3
- 15Taiwan44 cities19.2
- 16Chile42 cities18.6
- 17The Netherlands36 cities18.5
- 18Philippines3 cities18.4
- 19Germany256 cities18.3
- 20Hong Kong12 cities18.2
+ 29 more countries, 17.5 µg/m³ and below
- 40United States883 cities8.1
Not counted on this day, too few cities measured: Kyrgyzstan since 25 Mar 2026, Czechia since 18 Mar 2026, Spain since 11 Feb 2026 and Martinique since 30 Jan 2026.
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.