Petrochemical and Petroleum refining sector has become the backbone of the economical development. The costs of all the consumer goods are closely governed by cost of petroleum products. Diesel and petrol are two most widely used liquid fuels in the world. The cost of the fuel depends on the raw material. The optimization of the reaction carried out in these industries can save some cost and add to economy. The catalyst cracking is important part of these processes. Effective and efficient use of catalyst in desulphurization is key to economical operation of the process. In the developing countries the emission from these industries is important operational problem. The current review summarizes research and studies on these two aspects (catalyst and flue gas treatment) with respect to materials used, methodology and effectiveness.