(a) bio-mass contains stored energy as:

(i) Biomass (animal and plant products) is used to form biogas

(ii) Biomass does not have a good heating capacity, it produces a lot of smoke

Cow dung, various plant materials like residue after harvesting the crops, vegetable waste and sewage are decomposed in the absence of oxygen to give biogas

Biogas is stored, and drawn through pipes for use

It is an excellent fuel, gaseous state, non-polluting and high heating capacity

The slurry left behind can be used as manure, rich in nitrogen and phosphorus

(b) Biogas reduces pollution in the following ways:

It burns without smoke, leaves no residue like ash in wood, charcoal and coal burning.

It provides a safe and efficient method of waste disposal, besides supplying energy and manure.