The Scottish Greens have called for urgent action on air quality levels after a street in Edinburgh was named as the country's most polluted by environmentalists.

Friends of the Earth Scotland said air pollution levels on St John's Road in Corstorphine had "dramatically worsened" in the first half of the year.

Figures showed there were a recorded 35 "spike" incidents between January and June, where the levels soared.

The figures come as Edinburgh councillors are next week expected to determine a planning application for a new supermarket on the street with a car park.

Green MSP Alison Johnstone said: "It's shocking that we keep hearing news about alarming levels of pollution in our cities while thousands of Scottish people are dying prematurely because of poor air quality.

"We're not just talking about a minor environmental nuisance here - we're talking about a public health crisis.

"Despite continued warnings from health professionals, charities and community groups over the years, both Labour and SNP governments have failed to take this issue seriously.

"Green Councillors in Edinburgh have worked hard, with others, to get the city to introduce 20mph zones and to invest properly in cycling and walking infrastructure.

"We know that these policies work, and they now need to be implemented on a bigger, bolder scale.

"The Scottish Government must recognise its responsibilities and take urgent action to tackle this crisis."

Emilia Hanna said, Friends of the Earth Scotland air pollution campaigner, said St John's Road needed a "transport transformation".

"Priority should be given to walkers, cyclists and public transport users, and car use should be restricted through a low emission zone, which would require vehicles to meet cleaner emission standards or pay a fine," she said.

"This would create a cleaner, safer, and more attractive environment where everyone could breathe clean air."

A Scottish Government spokeswoman said: "Much progress has been made over recent years in improving air quality.

"However, areas of poorer air quality related to emissions from transport remain in many of our urban areas and the Scottish Government recognises that more needs to be done.

"Air pollution is harmful, and we continue to work closely with local authorities and other partners to improve air quality and the lives and well-being of communities and individuals across the country.

"In November the Scottish Government will publish 'Cleaner Air for Scotland - The Road to a Healthier Future' which will set out our plans for further action to tackle poor air quality over the coming years."