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 30 days to 25 Mar 2024: Pakistan 56.5 µg/m³, India 47.3 µg/m³ and China 47.2 µg/m³.
- 1Pakistan4 cities56.5
- 2India5 cities47.3
- 3China3 cities47.2
- 4Poland71 cities25.7
- 5Thailand15 cities, was 7225.3
- 6Serbia14 cities23.6
- 7Taiwan42 cities20.8
- 8Hong Kong7 cities19.8
- 9Chile42 cities18.9
- 10Montenegro3 cities18.8
- 11Mexico12 cities16.4
- 12Bulgaria4 cities16.0
- 13Hungary3 cities, was 913.4
- 14Singapore5 cities12.1
- 15Norway18 cities8.4
- 16United Kingdom49 cities8.2
- 17Japan500 cities8.2
- 18United States780 cities5.7
- 19Canada109 cities5.2
- 20Iceland4 cities3.3
Not counted on this day, too few cities measured: Australia since 25 Mar 2024, Peru since 24 Mar 2024, The Netherlands since 22 Mar 2024 and 21 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.