The UK’s average new car CO2 emissions fell 5.6% in the past year, according to a study by DrivenData.

Based on manufacturers’ claimed figures, average emissions now stand at 170.75g/km CO2, down from 180.90g/km in August 2009.

The 5.6% drop represents the fastest progress made by car makers in a 12-month period during the last five years.

In 2009, emissions were reduced by 3.6%, a small improvement on the previous year’s 3.3% fall. In August 2006, figures dropped just 2%, which DrivenData said underlined the advances made by manufacturers since.

However, with the Government’s 2012 reduction target looming – for an overall average of 130g/km CO2 – more work is needed. Based on this year’s improvement of 5.6%, DrivenData calculated that 2012 emissions would stand at 152.16g/km CO2.

DrivenData’s Daniel Stas said reaching the Government’s 2012 target would rely on the Lib-Con coalition itself.

He said: “Carmakers will be encouraged to see that they have collectively reduced average emissions at a faster rate this year.

“Much will depend on the emergence of plug-in hybrids and EVs (electric vehicles), which means the Government needs to commit wholeheartedly to funding an alternative fuel recharging network in the UK.”