Car manufacturers are being urged to make further progress in cutting CO2 emissions and reducing pollutants according to the latest report from EcoTest, the FIA Foundation's comprehensive environmental assessment programme for vehicles.

The report, which was launched at events across Europe in June, reveals the true environmental performance of a range of popular car models. The results show that the motor industry has further to go in order to achieve the lowest levels of CO2 emissions, pollutants and optimum fuel economy.

The report also shows that the latest models can have design upgrades, new safety features and changes to the engine which mean higher levels of CO2 emissions or pollutants, whilst other models have performed well on CO2 but have declined in terms of harmful pollutants such as nitrogen oxides, hydrocarbons and carbon monoxide. But many manufacturers are registering an improvement of up to 20 per cent when both CO2 emissions and pollutants are taken into account.

The greatest improvements were found in Opel/Vauxhall Zafira 1.7 CDTi and Peugeot 307 which both gained two stars in the EcoTest rating.

Pollutant ratings, CO2 emissions levels and fuel consumption figures for a range of models to be tested including the Renault Scenic, the Daihatsu Cuore, the Honda Accord Toure, the Audi A4 and others are available in the report.

While lower pollutant emissions of diesel vehicles have helped to make some headway, many petrol cars have also achieved good scores. CO2 emissions were also reduced in many vehicles.

FIA Foundation Director General David Ward said: “Car buyers shouldn't have to rely only on manufacturers to tell them the environmental impact of a 'green' vehicle. What people need is independently assessed, accurate and up to date information - and they need to know the full picture. There are cases where this year's model may not be making quite the progress expected. Indeed it's often the case that when a manufacturer makes design changes, we see a shift in emissions levels. However, consumers need to be told that this is the case - not kept in the dark.”

EcoTest puts cars through a rigorous driving cycle and collects data on the resulting CO2 emissions and pollutants. The test employs tougher measures than those required by the EU.