Madrid put restrictions on parking for non-residents in the city centre for the first time yesterday and enforced reduced traffic speeds for a second day in a move to control air pollution which has cloaked the city with brown smog.

The Spanish capital is relatively late to impose restrictions on traffic compared to other European cities. London introduced a congestion charge over a decade ago and has designated a low emission zone banning heavy diesel vehicles while Paris has pedestrianised some of its thoroughfares.

The Madrid council put on extra buses yesterday and asked people to leave their cars at home due to high levels of nitrogen dioxide, a poisonous gas released by diesel engines and linked to respiratory problems like asthma.

“It means a longer commuting time but everyone has to pull together to improve the situation,” said 39-year-old architect Arantxa Echevarria who came into work by bus rather than car yesterday.

Madrid’s metropolitan area has over three million cars in circulation, around one for every two people, plus nearly another million of trucks, vans and motorcycles.

A stretch of unseasonably sunny and clear weather and lack of rain has aggravated the poor air quality. Nitrogen dioxide is the only pollutant for which Madrid regularly exceeds EU warning levels.

Madrid was ranked one of the worst European cities for implementing measures on urban transport to improve air quality in a recent survey by environmental campaigners.

Zurich came top out of 23 while Madrid came 20th.