Many German cities have been allocating certain areas as environmental zones since 2009. It is only permitted to drive in these zones if your vehicle shows a environment sticker on the windscreen to certify it has an acceptable emission level. There are three different stickers and the colour depends of the exhaust emissions of your vehicle.The green sticker is for petrol cars made after 31/12/1992 and diesel cars made after 31/12/2005. The yellow sticker is for diesel cars made between 31/12/2000 and 1/1/2006 and the red sticker is for diesel cars made between 31/12/1996 and 1/1/2001.To indicate you are entering an environmental zone large signs will show which stickers you need to drive your car in that particular area. Please be aware of these signs, especially if you are driving an old diesel car or van as penalties are extremely high. The environment stickers are applicable for all vehicles except motorbikes. The stickers can be purchased on-line and via the German vehicle inspection authorities T Ü V and DEKRA.