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 15 Dec 2025: Pakistan 239.4 µg/m³, India 64.1 µg/m³ and North Macedonia 48.9 µg/m³.
- 1Pakistan14 cities239.4
- 2India238 cities64.1
- 3North Macedonia13 cities48.9
- 4Bosnia and Herzegovina4 cities44.7
- 5Ghana3 cities33.7
- 6Peru6 cities28.5
- 7Romania17 cities22.6
- 8Bulgaria7 cities22.4
- 9Hong Kong13 cities22.4
- 10Thailand72 cities21.6
- 11Slovenia12 cities, was 1221.5
- 12Mexico49 cities19.4
- 13Poland63 cities17.2
- 14Hungary12 cities16.2
- 15South Korea135 cities16.0
- 16Chile40 cities15.9
- 17Greece10 cities15.0
- 18Laos3 cities15.0
- 19Taiwan45 cities14.8
- 20Czechia9 cities, was 2311.9
+ 24 more countries, 11.5 µg/m³ and below
- 34United States862 cities, was 8696.9
Not counted on this day, too few cities measured: Montenegro since 15 Dec 2025, Philippines 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 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.