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 1 Aug 2023: Chile 42.7 µg/m³, Pakistan 27.9 µg/m³ and China 20.3 µg/m³.
- 1Chile44 cities42.7
- 2Pakistan4 cities27.9
- 3China3 cities20.3
- 4Peru4 cities19.0
- 5India5 cities14.9
- 6Singapore5 cities14.4
- 7Mexico42 cities, was 1214.2
- 8Hong Kong12 cities13.0
- 9Thailand11 cities12.7
- 10Greece8 cities12.2
- 11Malta4 cities12.0
- 12Serbia3 cities9.8
- 13Japan502 cities9.1
- 14Romania7 cities8.9
- 15United States746 cities8.8
- 16North Macedonia7 cities8.6
- 17Canada111 cities7.7
- 18Bulgaria6 cities7.2
- 19Hungary7 cities6.7
- 20Spain81 cities6.3
+ 14 more countries, 6.3 µg/m³ and below
Not counted on this day, too few cities measured: Italy since 28 Jul 2023, Martinique since 28 Jul 2023, Poland since 26 Jul 2023 and 5 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.