 Colonial administrator Herbert Hope Risley, an exponent of race science, used the ratio of the width of a nose to its height to divide Indians into Aryan and Dravidian races, as well as seven castes.The role of the British Raj on the caste system in India is controversial.The caste system became legally rigid during the Raj, when the British started to enumerate castes during their ten-year census and meticulously codified the system.