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The Government is being taken to the UK’s highest court today over obligations to meet European Union limits for air pollution.

It follows a hearing last year at the Supreme Court relating to breaches by the UK of EU limits for nitrogen dioxide (NO2), which is known to cause breathing and heart problems.

Legal action over the issue was brought by environmental campaign group ClientEarth against the Environment, Food and Rural Affairs Secretary, and centres on the Government's obligations under the Air Quality Directive to reduce levels.

In May 2013, the Supreme Court granted the group a declaration that the UK was in breach of its obligations over nitrogen dioxide.

Campaigners are hoping the Supreme Court will rule the Government must come up with new plans to tackle air pollution as soon as possible. The court could also rule the Government must bring forward the date in which targets have to be met.

At the hearing today a panel of judges, headed by president Lord Neuberger, will hear argument on behalf of ClientEarth and the Secretary of State in the light of rulings made by the CJEU - both sides are said to take "different views as to the interpretation of the judgment of the CJEU".

ClientEarth said it would "call on the Supreme Court to order the Government to produce a new plan which will deliver urgent cuts to the illegal levels of air pollution in towns and cities across the UK".

The EU directive at the centre of the case set limits to the level of various pollutants - the deadline for compliance with the limits for nitrogen dioxide was January 1 2010.

Each member state was required by the directive to define "zones" and "agglomerations" to which the pollutant limits would apply - Article 13 imposed an absolute obligation to ensure that limits and margins of tolerance for nitrogen dioxide were not exceeded in any zone or agglomeration after the deadline.

The limits imposed by the directive are based on scientific assessments of the risks to human health associated with exposure to nitrogen dioxide.

In the UK, road traffic and domestic heating are the main sources of nitrogen dioxide in most urban areas.

ClientEarth said air pollution caused 29,000 early deaths a year in the UK - more than obesity and alcohol combined.

The UK breached EU limits for nitrogen dioxide - a pollutant from vehicles and power stations - in 40 of 43 areas of the country in 2010.

Under plans drawn up by the UK to meet the Air Quality Directive rules, 16 areas including Greater London, Greater Manchester, Glasgow and the West Midlands would not even meet the pollution limits by a potential extended deadline of the start of this year.

The ruling by the European court found that the UK was in breach of EU law and should have created plans to tackle air pollution in those areas by January 1 this year at the latest.

It said the UK courts should order the Government to establish plans to cut nitrogen dioxide pollution as soon as possible.

ClientEarth has said under existing plans, some areas such as London, Birmingham and Leeds would not meet the pollution limits until 2030, 20 years after the original deadline of 2010.

Alan Andrews, ClientEarth lawyer, said in a statement about the latest hearing into its case: "We all have the right to breathe clean air and ClientEarth has spent the last four years fighting to uphold that right in court.

"The Government's current plans won't achieve legal limits for decades.

"Every year that goes by, thousands more people will die or be made seriously ill from heart attacks, asthma attacks, strokes and cancer.

"We need to get the most polluting diesel vehicles out of city centres as soon as possible for the sake of our health and our children's health."

Keith Taylor, Green MEP for South East England, said : "In the same week that the UK has experienced severe levels of air pollution it comes as no surprise that the Government are being taken to court because of a failure to act.

"The Green Party has been warning everyone for years about the serious health problems that are associated with air pollution.

"How many court cases will it take before the Government takes the issue seriously?"

He added: "We need bold measures to tackle this public health crisis such as making public transport free in cities and towns on days of high air pollution".

The issue the Supreme Court is to decide is whether, in areas where compliance with nitrogen dioxide limits could not be achieved by 1 January 2010, the directive required the Government to have prepared an air quality plan which demonstrates compliance by January 1 this year - and if so "what remedies must the court provide" where an air quality plan showing such compliance has not been prepared.

At the end of the one-day hearing the judges are expected to reserve their decision to be given at a later date.

Additional reporting Press Association.