Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen usually consisting of certain quantities of methane and other constituents Biogas can be produced from raw materials such as agricultural waste manure municipal waste plant material sewage green waste or food waste Biogas is a renewable energy source In India it is also known as Gobar Gas Biogas is produced by anaerobic digestion with methanogen or anaerobic organisms which digest material inside a closed system or fermentation of biodegradable materials This closed system is called an anaerobic digester biodigester or a bioreacto