According to BBC, manufacturers that are selling cars to the EU, must reduce their CO2 emissions drastically.
In 1998 the manufacturers and the EU voluntarily agreed to aim for average emissions of 140g/km by 2008/9, but are no longer expected to meet this target. This is because the 2005 level is 162 g/km, so it is unrealistic to expect a fall to 140 g/km by 2009.
Instead a new plan was agreed. The commission will propose a package of measures designed to bring emissions from the average new car down to 120g of CO2 per kilometre by 2012 - 25% below the 2005 level of 162g/km.
Carmakers would be be responsible for getting emissions down to 130g/km through the use better car technology, under the commission proposal.
Increased use of biofuels, better tyres and measures to ensure drivers change gear at the right time would help to save the extra 10g/km.