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 17 Nov 2023: Pakistan 94.4 µg/m³, India 88.9 µg/m³ and China 42.2 µg/m³.
- 1Pakistan4 cities94.4
- 2India4 cities88.9
- 3China3 cities42.2
- 4Thailand10 cities22.5
- 5Chile23 cities19.3
- 6Hong Kong12 cities, was 1215.4
- 7North Macedonia7 cities15.4
- 8Singapore5 cities14.0
- 9Mexico10 cities, was 3713.2
- 10Greece9 cities12.7
- 11Serbia3 cities11.6
- 12Romania6 cities11.3
- 13Czechia32 cities9.8
- 14Hungary8 cities9.7
- 15Bulgaria6 cities9.5
- 16Japan516 cities9.4
- 17Italy18 cities8.9
- 18Martinique3 cities8.9
- 19Slovakia27 cities8.7
- 20Lithuania4 cities8.0
+ 14 more countries, 7.7 µg/m³ and below
- 22United States772 cities7.7
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 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.