Question

why biogas is considered eco friendly if methane produces CO2 on oxidising.

Answer 1

Because biogas undergoes complete combustion major consituents

Co2 and h20 while

Methane is difficult to obtain

Answer 2

because it is form by waste we produce and reduce the pollution band also CH4 can be used as cooking gas and it releases little amount of CO2 that's not enough to pollute the environment that waste may pollute