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 24 Mar 2024: Pakistan 50.2 µg/m³, India 47.7 µg/m³ and China 47.2 µg/m³.
- 1Pakistan3 cities50.2
- 2India5 cities47.7
- 3China3 cities47.2
- 4Poland71 cities25.9
- 5Thailand15 cities, was 7225.0
- 6Serbia14 cities23.5
- 7Taiwan40 cities20.6
- 8Hong Kong8 cities20.3
- 9Chile43 cities18.8
- 10Montenegro3 cities18.3
- 11Bulgaria4 cities16.2
- 12Mexico13 cities16.0
- 13Hungary3 cities, was 913.5
- 14Singapore5 cities12.1
- 15Norway18 cities8.4
- 16United Kingdom50 cities8.1
- 17Japan498 cities8.0
- 18United States779 cities5.8
- 19Australia19 cities5.6
- 20Canada109 cities5.1
+ 1 more country, at 3.3 µg/m³
Not counted on this day, too few cities measured: Peru since 24 Mar 2024, The Netherlands since 22 Mar 2024, Belgium since 20 Mar 2024 and 20 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.