AdBlue® is a liquid solution composed of demineralised water and urea. This liquid is used to supplement diesel vehicles in order to drive ‘cleaner’. The toxic exhaust gases are converted into water and nitrogen. That way, you can sometimes still gain access to low-emission zones. One condition, however, is that the vehicle has an exhaust catalyst with SCR technology.
AdBlue® is carried in a separate tank and you can refill it yourself or by your local garage owner.