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 31 May 2023: Chile 36.9 µg/m³, Pakistan 35.9 µg/m³ and India 35.3 µg/m³.
- 1Chile44 cities36.9
- 2Pakistan4 cities35.9
- 3India5 cities35.3
- 4Mexico12 cities, was 4123.0
- 5Thailand11 cities, was 3721.9
- 6Brazil33 cities13.3
- 7Serbia3 cities13.2
- 8Greece7 cities11.9
- 9Belgium41 cities11.6
- 10Czechia35 cities11.1
- 11Slovakia26 cities10.6
- 12Malta3 cities10.2
- 13Hungary8 cities9.6
- 14Romania6 cities9.2
- 15Singapore6 cities9.1
- 16Austria30 cities9.0
- 17Bulgaria6 cities8.9
- 18Germany194 cities8.8
- 19Italy27 cities8.8
- 20Spain97 cities8.1
+ 11 more countries, the next at 8.1 µg/m³
- 22United States747 cities8.0
Not counted on this day, too few cities measured: Poland since 29 May 2023, Luxembourg since 27 May 2023, The Netherlands since 23 May 2023 and 6 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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.