Speed limits on two stretches of the M4 that were temporarily put in place to cut air pollution are to be made permanent.

The reduced 50mph speed limits were introduced on the motorway and on stretches of A-road last year as part of a Welsh government plan to cut high levels of nitrogen dioxide emissions.

Ministers had been ordered to take action after they failed to meet EU targets on air pollution.

The Welsh government's energy, environment and rural affairs minister, Lesley Griffiths, said in January that the trial speed limits on the M4 Newport, M4 Port Talbot, A494 Deeside, A483 Wrexham and A470 Pontypridd would be kept for as long as deemed necessary.

Now she has confirmed the 50mph limits will stay permanently across all five sites.


She said: "We will be enhancing communications around the reason for the speed restrictions and providing new permanent traffic sign layouts at all sites so that the public is aware of the importance of these measures."

In the meantime, the current speed limit in place will be retained through permanent traffic regulation orders, a Welsh government spokesman said.

Following Ms Griffiths' statement, Andrew Davies AM noted that the speed limits would be a "dream for many people" on the M4, adding: "I wish you well on your public information campaign, but, if you're saying about 50mph, most people would say you dare not get close to 50mph at most times of the day on that particular motorway."

In response, Ms Griffiths said her concern was that drivers were not keeping to the speed limits and did not understand why there were 50mph sites.

"I think we need signs saying, 'Poor air quality kills, reduce your speed'," she said.

Image: Thirty-six thousand deaths annually are linked to air pollution in the UK

The announcement came as the UK celebrated Clean Air Day with over 500 events across the country on 20 June.

Coordinated by the environment charity Global Action Plan, it saw events ranging from walking buses and electric vehicle roadshows.

Mayor of London Sadiq Khan also revealed that London would host its largest ever Car Free Day on 22 September.

He announced City Hall's plans to close 20km of streets across Central London, including Tower Bridge and much of the City of London, so the public can enjoy hundreds of free events without cars and traffic.