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 27 Dec 2023: Pakistan 152.6 µg/m³, India 129.4 µg/m³ and North Macedonia 65.3 µg/m³.
- 1Pakistan4 cities152.6
- 2India5 cities129.4
- 3North Macedonia7 cities65.3
- 4Serbia3 cities41.6
- 5China3 cities34.5
- 6Thailand9 cities33.5
- 7Greece10 cities22.4
- 8Mexico45 cities22.2
- 9Hong Kong13 cities20.9
- 10Italy24 cities, was 2819.2
- 11Chile45 cities18.1
- 12Romania8 cities16.2
- 13Bulgaria5 cities15.5
- 14Hungary9 cities9.8
- 15Spain108 cities9.4
- 16Brazil33 cities8.8
- 17Portugal18 cities8.5
- 18Malta4 cities8.4
- 19United States770 cities8.0
- 20Singapore6 cities7.1
+ 17 more countries, the next at 6.9 µg/m³
Not counted on this day, too few cities measured: Luxembourg since 5 Dec 2023 and Martinique since 1 Dec 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.