Long before smartphones and government apps, India used its vast postal network to persuade people to take part in one of the world's biggest statistical exercises: the census. Now, as India prepares for its 16th census - the eighth since independence in 1947 - a new exhibition revisits that forgotten history through stamps, postmarks and letters once used to rally citizens behind the national headcount. India begins huge census India's census: The good and bad news The exhibition, curated by