After devastating floods revealed the hidden cost of river sand extraction, a quiet shift began in India’s construction industry. M-sand—crushed stone used as a sustainable alternative—offered a solution, but old beliefs, trust gaps, and logistical barriers stood in the way. This is the story of how small builders, local masons, and a changing market are reshaping housing from the ground up.

The Affordable Housing & Technology focus area is about changing the way low-income families build and live. Here, our work is based on three initiatives: spreading bamboo construction, creating an inclusive housing industry, and building coalitions of impact.