A ‘car-free’ day in Paris led to a dramatic drop in both air and noise pollution - leading the mayor to propose more vehicle free days in the French capital.

For one day private cars - and motorbikes - with diesel or petrol engines were shunned from the city's streets in a bid to raise awareness of the dangerous levels of pollution the city suffers, and to showcase city life without motor cars, where pedestrians and cyclists instead have priority.

Paris Sans Voitures took place last Sunday ahead of the UN Climate Change Conference in Paris, whose goal is to agree a legally binding and universal agreement on climate change from all nations of the world.

It also followed one day in March where air pollution became so bad it made Paris into the world’s most polluted city for a brief period.

Airparif, which measures city pollution levels, said levels of nitrogen dioxide dropped by up to 40% in parts of the city on Sunday 27 September - and there was almost one-third less nitrogen dioxide pollution on the busy Champs Elyées than on a similar Sunday.

Bruitparif, which measures noise, said sound levels dropped by half in the city centre.

Police did not agree to allow the ban across the whole city, meaning that only about 30% of areas took part, but that did not dim the mayor’s enthusiasm for the project.

City mayor Anne Hidalgo said on Twitter: “We might envisage days without cars more often … perhaps even once a month.”

In its report for 2014, according to the Guardian, Airparif wrote: “Despite meteorological conditions favourable to the quality of air in 2014, 2.3 million French people are still exposed to levels of pollution that do not respect the rules, particularly in the case of (lead) particles and nitrogen dioxide. Those living in the Paris region and near major roads are the most affected.”

Jean-Francois Husson, head of the Sénat committee, said: ”There’s lots of work to do … Europe and states have to act.”

Christophe Najdovski, deputy mayor in charge of transport, said: “We’re behind on this and we cannot afford to be,” Najdovski said.

“We have to change people’s attitudes and behaviour. The fact is you don’t need a car to get around in Paris and there is no reason to use one most of the time. You can take public transport, bicycles and even walk.

“The young have a different relationship with cars. They are much less likely to buy a car and more interested in car-sharing and similar schemes.

“My dream Paris would be a city without cars. It may be idealistic, but we have to start somewhere. And this is the road we have to go down if we want to have a city we can live in.”