Mobile emission catalyst helps in emission reduction from automotive and stationary engines from many vehicles such as cars, trucks, commercial vehicles and buses. It reduces emission of various gases such as carbon dioxide (CO2), carbon mono oxide (CO), hydrocarbons (HC), oxide of nitrogen (NOx) and other gases which are produced due to incomplete combustion of fuel. Mobile emission catalyst can also operate at high temperatures range. Mobile emission catalytic converter contains a substrate or core with a honeycomb structure coated with catalyst materials. Mobile emission catalyst is formulated either by single metals or a combination of various active metals such as vanadium, platinum, rhodium, zeolites, oxides of tungsten, titanium and molybdenum. Mobile emission catalyst is mainly use in gasoline engines, diesel engines, motorcycles engine and utility engines.