SmogRank / History / City race
Cities in Czechia, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities in Czechia for PM2.5 over the 30 days to 22 Feb 2023: Bohumín 22.6 µg/m³, Český Těšín 22.5 µg/m³ and Havířov 22.2 µg/m³.
- 1BohumínMoravian-Silesian Region22.6
- 2Český TěšínMoravian-Silesian Region22.5
- 3HavířovMoravian-Silesian Region22.2
- 4DěčínÚstí nad Labem Region21.7
- 5Frýdek-MístekMoravian-Silesian Region21.6
- 6Valašské MeziříčíZlín21.4
- 7OstravaMoravian-Silesian Region21.0
- 8ZlínZlín20.5
- 9OlomoucOlomouc Region19.5
- 10BerounCentral Bohemia18.8
- 11Mladá BoleslavCentral Bohemia17.9
- 12Hradec KrálovéHradec Králové Region17.8
- 13Ústí nad LabemÚstí nad Labem Region16.7
- 14MostÚstí nad Labem Region16.7
- 15PraguePrague15.8
- 16ZnojmoSouth Moravian15.5
- 17PilsenPlzeň Region15.3
- 18ŽideniceSouth Moravian15.2
- 19LitvínovÚstí nad Labem Region15.2
- 20KladnoCentral Bohemia15.0
+ 5 more cities, 15.0 µg/m³ and below
Not counted on this day, too few days measured: Slatina since 31 Jan 2023. Days missing from the source archive fall in this window, so fewer countries are counted.
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. 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.