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 15 May 2026: Laos 47.3 µg/m³, Pakistan 44.5 µg/m³ and India 35.2 µg/m³.
- 1Laos3 cities47.3
- 2Pakistan14 cities44.5
- 3India209 cities35.2
- 4Chile46 cities33.1
- 5Peru6 cities28.4
- 6Thailand80 cities24.3
- 7Mexico50 cities19.3
- 8Kazakhstan4 cities18.6
- 9Malawi5 cities15.8
- 10Hong Kong13 cities15.1
- 11Taiwan44 cities14.4
- 12South Korea140 cities14.1
- 13Malta5 cities14.1
- 14Serbia8 cities13.4
- 15Brazil22 cities12.5
- 16Senegal3 cities12.2
- 17North Macedonia14 cities11.2
- 18Italy36 cities10.1
- 19Greece4 cities, was 129.6
- 20Hungary13 cities9.5
+ 28 more countries, the next at 9.5 µg/m³
- 40United States871 cities5.5
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 reader for China's network. Turkey's network doesn't answer requests from outside the country, so we can't read it. Most cities there are missing from this board, not clean. Why.