European citizens in many urban areas suffer from serious health impacts due to air quality issues. These are in part due to the fact that current engines, while certified on test stands according to the Euro standards in force, exhibit higher noxious emissions while driving, for example for NOx in cars powered by diesel engines or for particles in direct injections gasoline engines. The prize aim at spurring the development of engine and powertrain technologies using conventional fuels to reduce emissions of pollutants in real driving conditions to the lowest level possible, in order to improve air quality issues in European cities. This prize aims at reducing the pollution produced by the existing fleet by promoting the development of retrofittable technology (i.e. devices or modification of existing engines), addressing the existing diesel-powered fleet.