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 4 Aug 2026: Pakistan 37.1 µg/m³, Malawi 34.8 µg/m³ and Chile 26.4 µg/m³.
- 1Pakistan13 cities37.1
- 2Malawi5 cities34.8
- 3Chile47 cities26.4
- 4Nepal3 cities23.4
- 5India220 cities21.2
- 6Lebanon3 cities18.3
- 7Mexico46 cities16.7
- 8Slovakia39 cities15.0
- 9Italy30 cities14.9
- 10Malta5 cities14.8
- 11Brazil6 cities14.6
- 12New Zealand6 cities14.1
- 13Switzerland11 cities, was 313.6
- 14Kazakhstan4 cities13.2
- 15South Korea129 cities12.6
- 16Poland58 cities, was 1411.3
- 17Japan560 cities11.0
- 18Bosnia and Herzegovina5 cities10.8
- 19Hungary13 cities, was 410.7
- 20Austria46 cities10.1
+ 28 more countries, 9.9 µg/m³ and below
- 29United States851 cities8.7
Not counted on this day, too few cities measured: Spain since 22 Jul 2026, Ghana since 20 Jul 2026, Philippines since 19 Jul 2026 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.