LPG Liquid Petroleum Gas is made up of two major ingredients, namely propane and butane. The percentage of the two depends upon the season, as a higher percentage of propane is kept in winter and the same for butane in summer. It is a non-renewable fossil fuel that is prepared in a liquid state under certain conditions. The mixture is popularly known as propane for use in cars, and as LPG when it is used in cars and contains 90 percent propane in contrast to 2.5 percent butane. It is obtained from crude oil refining, and is also considered to be eco friendly because it doesn't cause any lead in the environment as a by-product.

LPG is used in homes as a cooking gas, and in cars as an alternate for petrol or diesel. With more and more people buying vehicles running on LPG, most of the gas stations provide refueling systems for LPG-run cars. LPG turns out to be a lot cheaper and efficient in comparison to petrol and diesel. After petrol and diesel, LPG is the 3rd most extensively used fuel for transportation the world over. The LPG-fitted cars are very popular in countries such as Japan, Italy, Canada, and Austria. However, people making use of LPG cylinders for cooking is not allowed, as the cylinders in many countries are available at fairly low rates compared to the ones available at gas stations.

Today, the LPG kits that are available in the market offer dual–fuelled or bi–fuelled systems. Automatic and manual switching to LPG from petrol or diesel or vice versa is available. Using LPG increases the fuel efficiency of the vehicle as LPG has a high octane value. It causes less corrosion of the engine because less water is vaporised, however, not everybody is aware of the safety risks and conservation issues that surround it. Being a flammable gas, LPG is potentially hazardous. The major disadvantage of using LPG in a vehicle is that because it doesn't use lead or any other substitute for combustion, it damages the valves, resulting in a decrease of the life of the engine. Moreover, as it is a low-density energy fuel, in comparison to petrol or diesel, LPG is consumed more but because of the subsidised rates available, it proves to be a lot cheaper.

Further, LPG is not recommended for mountains or any kind of rough terrain as it does not provide power and torque to the vehicle, as with other fuels. Using LPG means the vehicle drives 20% less than with other sources of fuel, resulting in more frequent refuelling. In contrast to petrol or diesel vehicles, starting is always a problem with LPG driven vehicles under 32 degrees Fahrenheit (cold conditions), because at lower temperatures it has a lower vapor pressure. It is considered to be eco-friendly as it reduces the emission of carbon dioxide by more than 40 percent. The use of LPG in homes and cars is growing day by day, so in future a gradual increase in its consumption can be seen.