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 28 Jan 2023: Havířov 19.3 µg/m³, Frýdek-Místek 18.9 µg/m³ and Český Těšín 18.7 µg/m³.
- 1HavířovMoravian-Silesian Region19.3
- 2Frýdek-MístekMoravian-Silesian Region18.9
- 3Český TěšínMoravian-Silesian Region18.7
- 4BohumínMoravian-Silesian Region18.7
- 5DěčínÚstí nad Labem Region18.2
- 6OstravaMoravian-Silesian Region17.4
- 7Valašské MeziříčíZlín16.7
- 8BerounCentral Bohemia15.6
- 9Mladá BoleslavCentral Bohemia15.4
- 10ZnojmoSouth Moravian15.1
- 11ZlínZlín14.9
- 12Hradec KrálovéHradec Králové Region13.9
- 13OlomoucOlomouc Region13.8
- 14ŽideniceSouth Moravian13.5
- 15Ústí nad LabemÚstí nad Labem Region13.2
- 16BrnoSouth Moravian13.1
- 17LitvínovÚstí nad Labem Region12.5
- 18MostÚstí nad Labem Region11.3
- 19PraguePrague11.1
- 20KladnoCentral Bohemia11.1
+ 4 more cities, the next at 11.0 µg/m³
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 reader for China's network. Turkey's network doesn't answer requests from outside the country, so we can't read it. Most cities there are missing from this board, not clean. Why.