Berlin’s Environmental Zone, also known as Berlin’s Umweltzone, refers to a region within the city of Berlin and has been deemed a low-emissions zone. This zone permits only vehicles that have an environmental badge, or a green sticker, to enter. The policy was put into place in January of 2008 due to the high density of Berlin’s inner city being affected by pollutants such as fine dust (PM 10) and nitrogen dioxide (NO2) threatening human health.