Volkswagen's German market share plunged in September

Sales of new cars in Germany plunged in September, official data showed Tuesday, as updated EU emissions tests turned into a bottleneck for many manufacturers.

New registrations were down 30.5 percent year-on-year last month, at 200,134 units, the KBA transport authority said.

But the September slump comes after a surge in August, as carmakers scrambled to bring older models onto the road before the new testing regime, known as WLTP, came into force.

Introduced in the wake of Volkswagen's "dieselgate" scandal, in which millions of diesel-fuelled cars worldwide were fitted with software to cheat lab-based tests, the new scheme aims to better reflect emissions in real on-road driving.

The disruption led to some upsets in the monthly figures.

As it struggled to get cars over the hurdle, Volkswagen's share for September fell to just 10.1 percent—compared with 19.1 percent for the year to date.

It was overtaken by high-end manufacturers BMW with 12.3 percent and Mercedes at 11.2 percent.

Even Peugeot-owned Opel—a historic German brand that usually appears as an also-ran in the home market—outpaced VW, with 10.2 percent of sales.

Meanwhile even with many fewer cars sold, diesel's continued to shrink, notching up just 29.3 percent of registrations compared with 64.3 percent for petrol.

Earlier Tuesday, ministers presented a plan aiming to avoid exclusion zones for older diesels in Germany's most polluted cities.

Politicians are counting on industry funded trade-in schemes for newer models and refits to dated exhaust systems to restore public confidence in the technology.