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 18 Nov 2025: Pakistan 214.5 µg/m³, India 61.8 µg/m³ and Bosnia and Herzegovina 41.1 µg/m³.
- 1Pakistan11 cities214.5
- 2India237 cities61.8
- 3Bosnia and Herzegovina4 cities41.1
- 4North Macedonia13 cities34.8
- 5Peru5 cities30.7
- 6Ghana4 cities24.2
- 7Mexico43 cities23.1
- 8Montenegro5 cities20.9
- 9Kosovo8 cities18.7
- 10South Korea140 cities17.7
- 11Bulgaria7 cities17.6
- 12Chile44 cities17.4
- 13Hong Kong13 cities16.7
- 14Hungary13 cities16.7
- 15Poland66 cities15.2
- 16Slovenia12 cities14.5
- 17Slovakia42 cities13.9
- 18Czechia11 cities12.7
- 19Greece12 cities12.1
- 20Malta4 cities11.5
+ 21 more countries, 11.1 µg/m³ and below
- 32United States262 cities, was 8696.1
Not counted on this day, too few cities measured: Canada since 17 Nov 2025, Romania since 17 Nov 2025, Philippines since 14 Nov 2025 and 7 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.