Munich  - The Volkswagen Passat 1.4 TSI EcoFuel with CNG natural gas drive is the first car to be given a top five-star rating in the annual eco hitlist compiled by the German automobile association (ADAC).

For the first time the Toyota Prius hybrid was dethroned in the test with the Passat CNG given three more points than the Japanese car.

Some 54 per cent of the cars tested were given a four-star rating for 2009 compared to only 14 per cent with the status in the year 2003 with new cars becoming cleaner from year to year, according to the ADAC.

Only two per cent of the cars achieved only a two-star rating with the last one-star rating given in the year 2006.

The ADAC however criticised some car makers for still offering new diesel cars without a diesel particulate filter and that low fuel consumption was often limited to special eco-fuel models.

A total of 900 cars were tested in what the association called "typical" driving conditions with special emphasis given to carbon dioxide and other emissions as well as the efficiency of the air conditioner. (dpa)