The importance of the Diesel fuel for meeting the energy demands needs no explanation. In the past 100 years or so, diesel fuel has become increasingly important to the human life. Due to increase in the number of vehicles, the environmental problems have become of immense concern for the whole world.We need to go for green fuels technology. There is great need to produce such fuels which cause less pollution and hence there is great need to produce Euro-II Diesel Oil. Hydrodesulfurization (HDS) is a catalytic chemical process widely used to remove sulfur from diesel fuel. It uses hydrogen to remove sulfur from sulfur containing compounds in the form of hydrogen sulfide gas. The very low sulfur levels required in diesel oil to meet environmental standards can only be achieved by HDS as it reduces sulfur contents to ppms. We are hopeful that this project will prove useful to the readers.