AdBlue® is an aqueous, colorless and odorless urea solution consisting of 32.5 percent of high-purity, crystalline urea and 67.5 percent demineralized water. With the urea solution the emission of nitrogen oxides (NOx) is reduced by up to 90 percent for diesel engines. The waterclear liquid is injected into the exhaust line and leads to a selective catalytic reaction (SCR). Thereby Nitrogen oxides and ammonia are converted into harmless water and Nitrogen.