Crude oil is a mineral oil of natural origin comprising a mixture of hydrocarbons and associated impurities, such as sulphur. It exists in the liquid phase under normal surface temperature and pressure and its physical characteristics (density, viscosity, etc.) are highly variable. This category includes field or lease condensate recovered from associated and non-associated gas where it is commingled with the commercial crude oil stream. Crude Oil comprises- petroleum oils and oils obtained from bituminous materials, other than crude; preparations n.e.c. containing by weight 70 per cent or more of these oils, such oils being the basic constituents of the preparations (Central Product Classification (CPC) Group 333).; - petroleum oils and oils obtained from bituminous minerals, crude (CPC Class 1201).