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 14 Jan 2025: Pakistan 122.7 µg/m³, India 89.1 µg/m³ and China 45.0 µg/m³.
- 1Pakistan4 cities122.7
- 2India5 cities89.1
- 3China4 cities45.0
- 4Thailand16 cities43.8
- 5Serbia25 cities33.6
- 6Romania10 cities28.4
- 7Hong Kong13 cities24.3
- 8Bulgaria5 cities23.1
- 9South Korea141 cities20.7
- 10United Kingdom5 cities19.8
- 11Ireland7 cities17.4
- 12Chile44 cities17.0
- 13Greece4 cities16.3
- 14Belgium45 cities16.1
- 15Taiwan43 cities14.6
- 16Slovenia12 cities14.3
- 17Mexico14 cities13.6
- 18Peru5 cities, was 1613.4
- 19Poland72 cities12.9
- 20The Netherlands24 cities12.6
+ 21 more countries, 11.5 µg/m³ and below
- 31United States799 cities7.2
Not counted on this day, too few cities measured: Lithuania since 13 Jan 2025, Czechia since 11 Jan 2025, Croatia since 11 Jan 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.