What explains the rise of sustained inequality, and what role does technology play in it? We address this question by examining a large-scale natural experiment: the construction of the world’s largest geographically contiguous irrigation infrastructure in British-era Punjab. Between 1880 and 1940, the British colonial administration established an extensive network of perennial canals across the Punjab plains, transforming vast tracts of previously agriculturally insecure or barren land into fertile, irrigated farmland.

Do integration policies that require migrants to demonstrate allegiance lead to more or less integration into the host society? In this paper, we study the effects of a symbolic change in birthright citizenship rules in France on the integration of second-generation immigrants. We exploit an exogenous reform that required second-generation immigrants to declare their willingness to become French as a condition to naturalize.