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 29 Jul 2023: Chile 44.1 µg/m³, Pakistan 25.4 µg/m³ and China 20.9 µg/m³.
- 1Chile44 cities44.1
- 2Pakistan4 cities25.4
- 3China3 cities20.9
- 4Malta4 cities20.6
- 5Peru4 cities19.7
- 6Greece8 cities15.5
- 7Mexico43 cities, was 1215.1
- 8Singapore5 cities14.6
- 9Thailand11 cities12.5
- 10Hong Kong12 cities12.4
- 11Serbia3 cities10.7
- 12United States742 cities10.7
- 13North Macedonia7 cities10.5
- 14Romania7 cities10.4
- 15India5 cities9.8
- 16Canada117 cities9.6
- 17Bulgaria6 cities8.5
- 18Slovakia27 cities8.5
- 19Hungary8 cities7.4
- 20Czechia27 cities7.3
+ 13 more countries, 6.6 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.