Hydrocracking is a refining process used to convert heavy crude oil into lighter, more valuable products like gasoline and diesel. It involves breaking down large hydrocarbon molecules in the presence of hydrogen and a catalyst, which helps speed up the chemical reactions. This process improves the quality of the fuel and increases the yield of useful products. During hydrocracking, the heavy oil is heated and mixed with hydrogen gas under high pressure. The catalyst facilitates the reaction, allowing the large molecules to split into smaller ones. This results in cleaner fuels that burn more efficiently and produce fewer emissions when used in vehicles and machinery.