EU car emissions fell 2.6 percent in 2012 from 2011, official figures showed on Wednesday, adding to a fierce Brussels debate on how quickly automakers can improve vehicle fuel efficiency.

The decline took average new car carbon emissions down to 132.2 grams per kilometer (g/km) in 2012, close to a 130 g/km target for 2015, according to the data from the European Environment Agency (EEA), which provides scientific data to guide policy-making.

With the 28-nation European Union likely to reach easily its 2015 target, the European Commission has proposed a CO2 target of 95 g/km for 2020.

But Germany, seeking to protect its luxury carmakers, insisted that the bloc tear up agreement reached in June on implementing the goal.

Member states are now trying to agree on a revised compromise on more fuel-efficient, less polluting vehicles.

Of the large manufacturers, Italy’s Fiat had the lowest average emissions (117 g/km), while France’s Renault and PSA Peugeot Citroen, at around 120 g/km in 2012, were also well below average, the EEA said.

At the other end of the scale, cars from Germany’s Daimler emitted 143 g/km and from Sweden’s Volvo averaged 142 g/km.

Although most major carmakers are on track, they will have to sell increasingly efficient vehicles to meet future targets.

Analysts say the 95 g/km 2020 goal as an average across the EU fleet is achievable using conventional combustion engines, but industry opinions are divided over whether pushing below that level could be done with existing engines or require a major increase in electric and hybrid vehicles.

“The average car sold in the EU is now over 20 percent more efficient than a decade ago, which is clearly good news,” EEA Executive Director Hans Bruyninckx said in a statement.

“The EEA looks towards a future transition of the mobility system beyond making efficiency gains in internal combustion engine technology.”