Sales of Volkswagen’s core passenger-car brand fell 4 percent in November, the biggest monthly drop this year, as demand contracted in eastern Europe and Latin America and VW switched to a new-generation Passat late in the month.

Deliveries of the VW namesake brand declined to 508,400 vehicles last month from 529,500 a year ago, the company said in a statement Monday, marking the fourth straight month of little or no volume growth at Europe’s No. 1 automaker.

VW brand sales slipped 0.4 percent in October and were almost flat in September and August.

“The challenging developments on markets worldwide will continue for the remainder of this year,” VW sales chief Christian Klingler said. The brand “was not entirely immune to their impact.”

Klingler said one of the main factors affecting deliveries in November was the Passat model change. VW has just introduced a new European version of the Passat, which is the region’s top-selling midsize car. Not only did people hold off buying the expiring Passat, but also demand for a new volume model tends to start slow and build gradually.

“The new Passat has been enjoying a strong tailwind since it made its market debut two weeks ago. We are in a positive mood, given the model’s winning performance in numerous comparison tests plus the high level of orders received from all over Europe,” Klingler said.

Political risks weighed on sales in central and eastern Europe, which declined 8 percent through November, with Russia alone posting a 20 percent drop, according to VW.

Deliveries in Latin America plunged 18 percent through November, with Brazil posting a 13 percent drop.

North American deliveries fell 6 percent in the first 11 months, with U.S. sales down 11 percent.

China sales increased 12 percent to 2.26 million.