What are some major sources of biomass fuel in developing countries?

In developing countries, major sources of biomass fuel include agricultural residues such as straw, husks, and other crop by-products, as well as wood and charcoal from trees. Animal dung is also commonly used as a biomass fuel, particularly in rural areas. Additionally, household waste and organic materials contribute to biomass fuel sources, providing energy for cooking and heating. These resources are often readily available and cost-effective for local communities.