 Corbridge concludes that British policies of divide and rule of India's numerous princely sovereign states, as well as enumeration of the population into rigid categories during the 10-year census, particularly with the 1901 and 1911 census, contributed towards the hardening of caste identities.Social unrest during 1920s led to a change in this policy.From then on, the colonial administration began a policy of positive discrimination by reserving a certain percentage of government jobs for the lower castes.