OpenStreetMap

OpenStreetMap (OSM) is the Wikipedia of maps — a free, editable map of the world built and maintained by a global community of volunteers. It contains roads, buildings, amenities, hospitals, schools, shops, bus stops, water bodies, administrative boundaries, and countless other features. For Indian civic research, OSM is extraordinarily powerful: combined with population grids (WorldPop) and government data, it enables detailed accessibility analysis (how many people live within 1 km of a hospital?), infrastructure mapping, and urban planning. OSM data for India is surprisingly comprehensive in major cities and steadily improving elsewhere, thanks to active mapping communities. The data is free, open (ODbL licence), and accessible through multiple APIs and bulk downloads.