The graph regarding the calorific value of certain fuels is given below. Analyse the graph and answer the following question. From the graph find out the most suitable fuel for household purpose. Justify your answer.

Considering the factor of renewable energy resource, and calorific value, biogas is renewable and has a comparatively higher calorific value, which makes it a suitable fuel for household purposes. biogas mainly consists of methane and carbon dioxide. Hence, when biomass is converted to biogas, the atmospheric pollution is minimised and a fuel of great calorific value is obtained.