BRUSSELS, Sept. 20 (Xinhua) -- Noisy cars and congested traffic were banished from the streets of the Belgian capital on Sunday, as the city celebrated its 15th annual Car Free Sunday.
For one day each year, a vehicle exclusion zone of 160 square kilometers is set up for the benefit of walkers, runners, cyclists and roller-bladers, with free public transport.
Only emergency vehicles, taxis and vehicles with a special dispensation were allowed to circulate, on the condition that they respect a 30 km per hour speed limit.
A normally traffic-clogged road tunnel on the city's inner ring road was transformed into a dancefloor with live DJs, while part of downtown Brussels became a circuit for skaters and BMX-riders.
The initiative comes after a 2014 study by traffic monitor Inrix found Brussels is the congestion capital of Europe, with the average driving wasting 83 hours a year in traffic.
However, campaign group CleanAirBXL says the "token action" of a car-free day is not enough to solve the city's air pollution problem.
On Sept. 21, the group will be offering cups of dirty water to passers-by in the European district of Brussels to raise awareness of the Belgian capital's poor air quality.
CleanAirBXL said in a news release: "Even if they refuse to drink this water, they are breathing more than 10,000 litres of polluted air a day, because they live or work in a city which well exceeds World Health Organization's limits, and is in breach of European air quality legislation."
It added: "By the end of October, the Brussels Capital Region will finalize its proposed first Regional Air-Climate-Energy plan, but the current plan is not good enough to really clean up the air for citizens and vulnerable groups like children or pregnant women in particular."
The campaign group has started a petition, which has been signed by more than 3,500 people, to demand more effective measures.
Meanwhile, Car Free Sunday has inspired Paris to follow suit.
During a visit to Brussels in January, Paris mayor Anne Hidalgo announced that the French capital would launch an annual car-free day. The first edition in Paris is on Sept. 27.