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 26 Jan 2024: Pakistan 228.9 µg/m³, India 84.2 µg/m³ and North Macedonia 52.6 µg/m³.
- 1Pakistan4 cities228.9
- 2India5 cities84.2
- 3North Macedonia7 cities52.6
- 4China3 cities43.3
- 5Thailand10 cities41.2
- 6Montenegro3 cities38.9
- 7Serbia12 cities, was 337.6
- 8Romania7 cities26.1
- 9Peru5 cities25.7
- 10Hong Kong13 cities25.4
- 11Bulgaria6 cities24.2
- 12Poland63 cities23.7
- 13Greece10 cities20.3
- 14Italy25 cities19.4
- 15Czechia33 cities19.3
- 16Hungary9 cities19.3
- 17Norway20 cities19.3
- 18Slovakia27 cities18.8
- 19Chile44 cities17.8
- 20Mexico11 cities, was 4415.3
+ 22 more countries, the next at 15.0 µg/m³
- 36United States771 cities6.9
Not counted on this day, too few cities measured: Reunion since 20 Jan 2024, Malta since 6 Jan 2024 and Martinique since 8 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.