Though the census count of human population seems to be an apolitical affair, yet it is invariably coloured by political overtones of various hues. Accordingly, both the detail and the quality of population data carry an overt as well as covert imprint of political considerations. Thus, for a proper comprehension of population patterns, both social and spatial, it is imperative to understand the politics of collection of such data. This paper attempts to understand mainly the following aspects of politics of population census data in India: (i) categorisation of census materials; (ii) changes in census categories over time; and (iii) changes in details of data by caste and religion.