Most of downtown Ljubljana, Slovenia's capital, has been closed to cars for more than a decade. Since 2007, a pedestrian zone has been set up in the centre of the Slovenian capital.
It gradually expanded to 19 hectares and today, the city boasts a network of more than 300 km of bike paths. On the largest boulevard closed to traffic, Slovenska Avenue, emissions of soot carbon - fine particles responsible for lung cancer - have been reduced by at least 70%.