What is it that a big city offers? Economic opportunities that promise a better life for the innumerable hopefuls who crowd its streets; and the infrastructure to keep pace with the changing landscape of aspirations. This is the seductive promise, too, of the central government’s Smart Cities Mission. This is what had drawn UPSC aspirants Shreya Yadav, Nevin Dalwin and Tanya Soni from Uttar Pradesh, Kerala and Telangana to the national capital to study at Rau’s IAS Study Centre in Old Rajinder Nagar. Their deaths by drowning in the Centre’s…