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 17 Nov 2024: Pakistan 120.1 µg/m³, India 97.7 µg/m³ and Bosnia and Herzegovina 43.6 µg/m³.
- 1Pakistan4 cities120.1
- 2India4 cities97.7
- 3Bosnia and Herzegovina4 cities43.6
- 4Serbia25 cities39.8
- 5Thailand16 cities32.0
- 6China3 cities29.6
- 7Slovenia12 cities26.1
- 8Hungary11 cities, was 425.1
- 9Slovakia40 cities22.6
- 10Croatia5 cities22.0
- 11Romania10 cities21.3
- 12Poland76 cities20.8
- 13Chile46 cities18.7
- 14Mexico14 cities18.0
- 15Hong Kong12 cities17.9
- 16Peru16 cities17.2
- 17South Korea141 cities16.6
- 18Czechia36 cities15.8
- 19Taiwan43 cities14.3
- 20Singapore5 cities14.0
+ 26 more countries, 13.6 µg/m³ and below
- 41United States810 cities5.6
Not counted on this day, too few cities measured: Italy since 27 Oct 2024.
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.