On January 4, a short circuit sparked a fire that tore through the Naya Nagar neighborhood of Mumbai’s Dharavi slum, destroying more than 50 homes. Afterwards, a group of Dharavi girls wanted to prevent such a disaster from happening again. They realized that part of the problem was information. If residents could detect fires when they started, they could stop them before they spread. But how could girls in one of the poorest parts of the world, rife with gender-based discrimination, make a difference? They began to code a mobile app.