This document discusses low-cost building materials and construction techniques for developing affordable housing. It begins by outlining common problems in developing countries like population growth, urbanization, and shortage of affordable materials. It then lists several alternative building materials that can help address these issues in a more sustainable and cost-effective way, such as fly ash bricks, hollow concrete blocks, bamboo, and composites. The document emphasizes selecting materials that are locally available, use recycled waste, and require less energy intensive manufacturing to reduce costs while maintaining quality. Government policies and initiatives for developing low-cost and affordable housing are also mentioned.