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 12 May 2026: Laos 59.3 µg/m³, Pakistan 44.6 µg/m³ and India 35.7 µg/m³.
- 1Laos3 cities59.3
- 2Pakistan14 cities44.6
- 3India209 cities35.7
- 4Chile47 cities30.4
- 5Peru6 cities28.2
- 6Thailand80 cities25.6
- 7Mexico53 cities19.2
- 8Kazakhstan4 cities18.8
- 9Malta5 cities18.7
- 10Hong Kong13 cities15.5
- 11Malawi5 cities15.1
- 12Taiwan44 cities14.5
- 13Serbia8 cities14.4
- 14South Korea141 cities14.3
- 15Senegal3 cities13.0
- 16North Macedonia14 cities12.0
- 17Italy36 cities10.8
- 18Hungary13 cities10.6
- 19Slovakia42 cities10.0
- 20Romania28 cities9.9
+ 28 more countries, 9.4 µg/m³ and below
- 40United States870 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.