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 27 Nov 2023: India 100.3 µg/m³, Pakistan 98.0 µg/m³ and China 39.2 µg/m³.
- 1India4 cities100.3
- 2Pakistan3 cities98.0
- 3China3 cities39.2
- 4Thailand10 cities25.3
- 5North Macedonia7 cities21.9
- 6Chile34 cities18.8
- 7Hong Kong13 cities17.6
- 8Serbia3 cities15.7
- 9Mexico39 cities15.3
- 10Brazil30 cities13.4
- 11Romania7 cities12.2
- 12Greece8 cities12.0
- 13Singapore6 cities11.5
- 14Bulgaria6 cities11.4
- 15Italy20 cities10.6
- 16Martinique3 cities10.4
- 17Hungary7 cities10.1
- 18Lithuania4 cities9.4
- 19Japan512 cities9.2
- 20Czechia28 cities8.9
+ 15 more countries, the next at 8.9 µg/m³
- 22United States772 cities7.6
Not counted on this day, too few cities measured: Malta since 11 Nov 2023, Ireland since 6 Nov 2023, Peru since 21 Oct 2023 and Poland since 8 Oct 2023.
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.