The European Commission is planning a minimum tax on fuel for member states which would mean a rise in diesel prices. Under the plans, a new tax based on the carbon content of fuels would apply across member states, at a minimum of €20 per tonne of carbon dioxide. This is likely to affect diesel more than petrol, because most countries currently tax diesel more lightly. Connie Hedegaard, European commissioner for climate change, said: "It will encourage energy efficiency."