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 30 days to 17 May 2026: Pakistan 43.9 µg/m³, Laos 38.1 µg/m³ and India 35.0 µg/m³.
- 1Pakistan15 cities43.9
- 2Laos3 cities38.1
- 3India217 cities35.0
- 4Chile46 cities34.7
- 5Peru6 cities29.2
- 6Thailand79 cities22.3
- 7Kazakhstan4 cities19.3
- 8Mexico46 cities18.6
- 9Malawi5 cities16.1
- 10Hong Kong13 cities14.9
- 11South Korea137 cities14.4
- 12Taiwan44 cities14.0
- 13Malta5 cities13.8
- 14Senegal3 cities12.5
- 15Serbia8 cities12.4
- 16Brazil6 cities11.1
- 17North Macedonia14 cities10.5
- 18Greece5 cities, was 129.8
- 19Italy38 cities9.2
- 20Japan575 cities9.2
+ 28 more countries, 9.0 µg/m³ and below
- 37United States869 cities5.6
Not counted on this day, too few cities measured: Lithuania since 12 May 2026, Poland since 23 Apr 2026, Ghana since 15 Apr 2026 and 2 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.