Uncertainty over future taxation levels on diesel vehicles and a shortage of particulate filters has caused a marked decline in the share of diesel vehicles in Germany since the beginning of 2005, reports Automobilwoche.

According to official government figures the diesel share of new car registrations fell to 39% in July 2005, down from 48.2% in January 2005.

Some brands are more affected than others. The diesel share of Audi and Mercedes new registrations fell five percentage points, while Nissan, Volkswagen, Renault, Ford, Citroen and BMW dropped more than ten points.

The newspaper reports that many OEMs are only offering particulate filters from the autumn, and that a shortage of particulate filters means that there are excessive lead times on many models. Customers that are not willing to wait for their new car are opting for a petrol car, rather than a diesel without a filter.

There has been an on-going debate in Germany this year over the health effects of diesel vehicles without filters after pollution levels in Munich and Stuttgart exceeded EU limits earlier this year. Calls have been made for diesels with filters to receive tax breaks.