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 2024: Pakistan 104.6 µg/m³, India 79.5 µg/m³ and Bosnia and Herzegovina 57.6 µg/m³.
- 1Pakistan4 cities104.6
- 2India5 cities79.5
- 3Bosnia and Herzegovina4 cities57.6
- 4Serbia25 cities40.6
- 5Thailand16 cities30.4
- 6China3 cities27.6
- 7Slovenia12 cities27.5
- 8Romania10 cities24.4
- 9Hungary11 cities, was 424.0
- 10Croatia5 cities22.2
- 11Slovakia40 cities20.4
- 12Chile46 cities18.8
- 13Poland76 cities17.9
- 14Mexico12 cities17.8
- 15Peru16 cities17.6
- 16Kosovo8 cities17.1
- 17Hong Kong12 cities16.3
- 18Bulgaria8 cities15.5
- 19South Korea141 cities15.2
- 20Taiwan43 cities14.6
+ 27 more countries, 12.9 µg/m³ and below
- 40United States808 cities6.0
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.