FCA Group, Ford and Volkswagen led a 4.6 percent decline in European car registrations in January, industry data showed, dampened by an economic slowdown in euro zone economies and consumer jitters over Brexit and trade.

Registrations dropped to 1.20 million cars in the European Union (EU) and European Free Trade Association (EFTA) countries from 1.25 million a year earlier, the Brussels-based Association of European Carmakers (ACEA) said on Friday.

Fiat Chrysler sales fell by 14.9 percent, Ford by 6.6 percent and Volkswagen Group by 6.4 percent, according to the data. Renault’s alliance partner Nissan also recorded a 24.7 percent decline.

The drop came after the tougher new Worldwide Harmonised Light Vehicle Test Procedure (WLTP) became mandatory from the start of September, forcing some carmakers to halt deliveries of some models that had yet to be certified.