SKOPJE, Jan. 20 (Xinhua) -- Starting from Sunday, the Macedonian capital city of Skopje will offer free public transport until air pollution level drops, the spokesman of the city Valon Salihu said in a press conference.

Salihu said across the city all construction work is banned and parking fees are doubled.

Macedonian government said in an official press release on Sunday that they have decided to postpone the start of the school semester for two days due to the hazardous air pollution levels across the country.

Classes at all private and public schools are cancelled for Jan. 21 and 22, said the press release.

Meanwhile in Skopje, every classroom in 23 high schools will start the new semester with air purifiers. City officials said a total of 572 air purifiers, at an investment of 11 million Macedonian Denar (around 203,000 U.S. dollars), will be used in the high schools for the young generation, considering that they spend one-third of their days at school.

On Saturday the air quality index reached the 430. Air level is considered hazardous when it is higher than 300.

On Friday, Skopje mayor issued a health advisory due to the heavy levels of air pollution and urged the citizens to avoid outdoor activities and use public transport.