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 16 Dec 2025: Pakistan 236.9 µg/m³, India 64.7 µg/m³ and Bosnia and Herzegovina 59.1 µg/m³.
- 1Pakistan14 cities236.9
- 2India241 cities64.7
- 3Bosnia and Herzegovina4 cities59.1
- 4North Macedonia14 cities57.2
- 5Ghana3 cities32.7
- 6Peru6 cities29.3
- 7Romania17 cities24.9
- 8Bulgaria7 cities22.3
- 9Hong Kong13 cities22.2
- 10Slovenia12 cities, was 1222.1
- 11Thailand71 cities20.7
- 12Poland62 cities19.8
- 13Mexico50 cities19.6
- 14South Korea137 cities17.6
- 15Laos3 cities15.9
- 16Chile39 cities15.7
- 17Taiwan45 cities15.7
- 18Greece10 cities15.6
- 19Hungary12 cities15.4
- 20Philippines3 cities12.9
+ 25 more countries, the next at 12.3 µg/m³
- 34United States864 cities7.1
Not counted on this day, too few cities measured: Malta since 16 Dec 2025, Montenegro since 15 Dec 2025, Sweden since 14 Dec 2025 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.