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 23 Mar 2024: Pakistan 51.2 µg/m³, India 47.9 µg/m³ and China 46.0 µg/m³.
- 1Pakistan3 cities51.2
- 2India5 cities47.9
- 3China3 cities46.0
- 4Poland71 cities26.1
- 5Thailand15 cities, was 7224.8
- 6Serbia14 cities23.5
- 7Taiwan38 cities20.9
- 8Hong Kong11 cities20.6
- 9Peru5 cities19.1
- 10Chile43 cities18.8
- 11Montenegro3 cities18.2
- 12Bulgaria4 cities16.6
- 13Mexico12 cities14.8
- 14Hungary3 cities, was 913.4
- 15Singapore5 cities12.1
- 16Norway18 cities8.5
- 17United Kingdom47 cities8.2
- 18Japan497 cities7.8
- 19United States781 cities6.0
- 20Australia20 cities5.6
+ 2 more countries, 5.2 µg/m³ and below
Not counted on this day, too few cities measured: The Netherlands since 22 Mar 2024, Belgium since 20 Mar 2024, Switzerland since 20 Mar 2024 and 19 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.