At its heart has been a robust campaign to deliver every citizen a unique identification number, called the Aadhaar. The initiative, begun in 2009 under Mr. Modi’s predecessor, Manmohan Singh, was pushed forward by Mr. Modi after overcoming years of legal challenges over privacy concerns.

The government says about 99 percent of adults now have a biometric identification number, with more than 1.3 billion IDs issued in all.