SKOPJE -- Macedonia has introduced emergency measures against dense clouds of pollution that envelope its cities.
The annual winter smog problem that besets cities in the Western Balkans is blamed on a mix of coal burning, aging industry, and high-polluting emissions from older vehicles.
Macedonia's government says residents of Skopje and Tetovo have been granted free travel on trains and buses to discourage the use of cars.
People with chronic illnesses and pregnant women are excused from work and outdoor sports activities have been temporarily banned.
A World Health Organization (WHO) study published early in 2017 listed Skopje among 10 European cities with the highest concentration of toxic particles.
Skopje and four other Balkan cities on that list rely upon high-polluting lignite coal for heat during winters -- a holdover from decades of communist rule in the former Yugoslav republics.
Sarajevo, Tuzla and Zenica in Bosnia-Herzegovina, and Kosovo's capital, Pristina, also suffer from similar high levels of air pollution.
A recent study by the Health and Environment Alliance (HEAL) found 16 aging, communist-era lignite power plants in former Yugoslav republics emit as much pollution as all 296 power plants in the European Union.
As part of their bids to join the EU, governments of ex-Yugoslav republics have pledged to reduce emission levels.
With reporting by Reuters and Balkan Insight