Explanation: Biogas is an energy-rich gas produced by anaerobic decomposition of biomass.

· Sources of biogas are agriculture residue, cattle dung, sugarcane press mud, municipal solid waste, sewage treatment plant waste.

· It can be burnt directly as a fuel, or purified and upgraded by removing carbon dioxide, hydrogen sulfide, and then compressed to make compressed Biogas (CBG).

Source: FORUMIAS