Catalytic Convertor is used to reduces the Vehicular emissions that contains, Oxides of Nitrogen(NOX), Carbon Monoxide (CO), Hydrocarbon (HC),Particulate matter(PM), Sulphur dioxide(SO2) and other products of combustion.There arevarious types of Catalytic Convertors are Three Way, SCR (Selective Catalytic Convertor), Lean NOx Catalyst. Among these technologies, urea selective catalytic reduction is one of the most promising systems which have been proved of being able to reduce more than90% of NOx emissions. The Obtained result shows, SCR setup reduces NOx highly, carbon monoxide and unburned hydrocarbon by using urea injection and compressor setup.