The European Commission is taking the UK to Court for failing to reduce emissions at one of its power stations.
It said the Aberthaw coal-fired power plant in Wales exceeded the limits of the toxic pollutant nitrogen dioxide (NOx).
Under EU rules, member states had until 1st January 2008 to reduce emissions of a number of pollutants from power plants.
The Aberthaw power station currently operates under a permit which sets a NOx emission limit of 1,200mg per normal cubic metre (Nm3) – more than twice the 500mg/Nm3 limit set out by the Commission.
It said in a statement: “The Commission welcomes more recent indications from the UK authorities that investments will be made to upgrade the plant but at present the plant continues to operate under a permit which allows it to emit high levels of the toxic gas NOx. The Commission is therefore referring this case to Court.”
The Department for Environment, Food & Rural Affairs (Defra) added it would “continue to work with the European Commission”.