Since the 1st January 2008 a Low Emission Zone has been introduced in Cologne. This comprises the city centre as well as parts of the districts of Deutz and Mülheim. Traffic restrictions apply within this zone in order to permanently improve the air quality.
The regulations regarding the Low Emission Zone will apply for all Cologne residents and visitors, also those from abroad. This is why you should inform yourself about the regulations at your destination before your departure.