Carbon dioxide (CO2) emissions from new cars are falling, but not at a fast enough rate to meet reduction targets, it was revealed today.

Average new car CO2 emissions fell by two grams per kilometre in 2005, a report from the Society of Motor Manufacturers and Traders (SMMT) showed.

But the SMMT said that the percentage fall compared with the figure for 2004 was not a big enough reduction to achieve voluntary Europe-wide targets.

The target, agreed in 1998, is to reduce CO2 emissions from new cars by 25% by 2008 compared with the emission figure in 1995.

However, the report did show that various energy and waste levels associated with car production had halved in the period 2001 to 2005.

SMMT chief executive Christopher Macgowan said today: "We have made progress in 2005, and on some environmental measures this has been significant.

"However, our report is also transparent about the areas where improvements can be made. Our business responsibilities are changing. We will continue to look at how we report annually, consult with stakeholders to make improvements and track progress through production, use and on to vehicle disposal."