ILLEGAL air pollution levels in Glasgow are to be challenged at the UK Supreme Court on Thursday.

Environmental group ClientEarth is taking the UK Government to court over illegal levels of nitrogen dioxide in Glasgow and 15 other British cities and regions, in breach of EU limits.

This week's hearing is the culmination of a four-year battle in UK and EU courts and follows last year's ruling from the European Court of Justice which held that the UK must achieve air quality standards in the 'shortest time possible'

The Government's own estimates show that air quality in Glasgow will continue to break EU standards for nitrogen dioxide (NO2) until 2025 - 15 years after the original deadline.

Average levels of NO2 this year in the Glasgow Urban Area will be 74 micrograms per cubic metre (μg/m3) at the most polluted spots. The legal limit is 40 μg/m3.

A recent study by Friends of the Earth named Hope Street in Glasgow as Scotland's most polluted street.

Air pollution has been linked to coronary artery disease, heart attacks and strokes, and has been blamed for causing more than 300 deaths per year in the city.

ClientEarth is calling on the Court to order the Government to produce a new plan showing how it will make cuts in air pollution in UK cities.

Alan Andrews, ClientEarth lawyer, said: "Politicians in Holyrood and Westminster need to work together to find a solution. Levels of pollution in Glasgow are not only harmful to health, they're also illegal."

A spokeswoman for the Scottish Government said they were making progress in partnership with councils.

She added: "Data shows that significant reductions in air pollutants have been achieved since 1990 and the action we are taking will secure further reductions."

A spokeswoman for Glasgow City Council said: "The issues around air quality are often directed towards local authorities, but the really big policy drivers are in the hands of central or devolved government. Councils need to be given the appropriate powers and resources to address these issues."