LPG or (Liquified Petroliem Gas) is considered as a clean and ideal fuel.LPG is a mixture of saturated and unsaturated hydrocarbons (butane and commercial propane) hydrocarbon contains hydrogen and carbon which BURN to produse water and carbon dioxide which will not produce any kind of smoke and it will not pollute air.Smoke consists of unburnt carbon and fine particles of non gaseous oxides. Gases such as methane and propane consist of short hydrocarbon chains with relati vely low amounts of carbon. If there is a reasonable amount of oxygen, they will burn to form carbon dioxide and water, which are both colourless gases at these temperatures. while in case of wood or petroleum CHINS FORMED are long so full burning of carbon will not TAKE PLACE and produse smokes which are very harmful. Another thing is gaseos fuels are very ideal they produse less smokeproduces more heatwhile solid fuels like coal or wood are not ideal fuelsthey produce lot smoke produces less heat it is also harmful for environment.