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 Aug 2026: Pakistan 38.6 µg/m³, Malawi 33.0 µg/m³ and Chile 25.4 µg/m³.
- 1Pakistan13 cities38.6
- 2Malawi5 cities33.0
- 3Chile47 cities25.4
- 4Nepal3 cities22.7
- 5India216 cities20.6
- 6New Zealand6 cities16.9
- 7Mexico48 cities16.0
- 8Lebanon3 cities15.9
- 9Malta5 cities15.2
- 10Brazil6 cities15.1
- 11Italy30 cities15.0
- 12Slovakia39 cities13.6
- 13Switzerland11 cities, was 313.0
- 14Kazakhstan4 cities12.9
- 15South Korea127 cities11.7
- 16Japan557 cities10.9
- 17Poland58 cities, was 1410.0
- 18Bosnia and Herzegovina5 cities9.9
- 19Hungary13 cities, was 49.9
- 20Martinique3 cities9.9
+ 27 more countries, 9.7 µg/m³ and below
- 28United States849 cities8.6
Not counted on this day, too few cities measured: Latvia since 2 Aug 2026, Spain since 22 Jul 2026, Ghana since 20 Jul 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.