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 3 May 2026: Pakistan 33.9 µg/m³, Chile 32.9 µg/m³ and Peru 32.6 µg/m³.
- 1Pakistan15 cities33.9
- 2Chile46 cities32.9
- 3Peru6 cities32.6
- 4India217 cities30.6
- 5Laos3 cities30.4
- 6Thailand84 cities22.0
- 7Malawi5 cities20.9
- 8Mexico45 cities19.7
- 9South Korea139 cities16.0
- 10Kazakhstan4 cities15.8
- 11Taiwan44 cities14.4
- 12Serbia8 cities11.8
- 13Hong Kong13 cities11.7
- 14United Kingdom5 cities11.0
- 15Czechia27 cities10.4
- 16New Zealand6 cities9.9
- 17Italy39 cities9.7
- 18Senegal3 cities9.7
- 19Brazil6 cities9.6
- 20Malta5 cities9.6
+ 30 more countries, 9.5 µg/m³ and below
- 40United States848 cities5.1
Not counted on this day, too few cities measured: Poland since 16 Apr 2026, Ghana since 8 Apr 2026, Philippines since 6 Apr 2026 and Kyrgyzstan since 25 Mar 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.