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 May 2026: Pakistan 42.9 µg/m³, Chile 38.6 µg/m³ and India 33.3 µg/m³.
- 1Pakistan14 cities42.9
- 2Chile46 cities38.6
- 3India229 cities33.3
- 4Peru6 cities22.0
- 5Mexico38 cities18.1
- 6Kazakhstan4 cities15.6
- 7South Korea130 cities15.3
- 8Brazil6 cities14.8
- 9Malawi5 cities14.8
- 10Thailand78 cities14.0
- 11Lebanon3 cities12.0
- 12New Zealand6 cities11.9
- 13Taiwan44 cities11.5
- 14Laos3 cities11.0
- 15Japan573 cities10.9
- 16Hong Kong13 cities10.8
- 17Malta5 cities9.8
- 18Martinique3 cities9.6
- 19Greece10 cities9.3
- 20Serbia8 cities9.1
+ 27 more countries, 7.7 µg/m³ and below
- 27United States850 cities5.7
Not counted on this day, too few cities measured: Czechia since 14 May 2026, Slovenia since 12 May 2026, Senegal since 10 May 2026 and 5 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.