The air breathed by an average Pole may not be Europe’s dirtiest. According to the European Environment Agency, Balkan nations like Serbia do worse on metrics like years of life lost per person. However, Poland’s effluvia stand out for their geographical spread. Of the 100 European cities with the most air pollution, 29 are Polish.

Poland’s nationwide sheet of smog stems from its use of coal—often of the cheap, extra-dirty sort—for home heating, rather than the cleaner natural gas common in nearby countries...

The Economist: Poland’s coal-fired home heating creates widespread pollution