Summary: My project ‘Science of Difference: Producing Racial and Religious Identities Through Nationalist Science, India 1920-2020’ interrogates the role of physical anthropology, serology, genetic anthropology and statistics, in naturalizing religious and caste hierarchies. Under colonial rule, Indian scientists rejected the claim that Europeans were racially superior to Indians. However, they did not dismiss race as a scientific object. Instead, from the 1920s, Indian scientists sought to measure the extent of racial mixing between castes and religious groups. Asking where Indian Muslims had come from and whether Christians were indigenous, they calculated physical features, blood-group distribution, and genetic variations to produce a map of the nation’s racial and religious past. My project contributes to the aim of the grant scheme by analyzing how science and religion were co-constituted. That is, how scientific objectivity was built through measuring religious differences, while religious hierarchy came to be constituted as natural through its uncritical