Special Intensive Revision

Special Intensive Revision or the SIR is an exercise undertaken by the Election Commission of India to verify and revise electoral rolls through house to house enumeration, pre-filled forms, and verification of old voter data. The SIR aims to ensure that electoral rolls across India are accurate, by eliminating the names of deceased, permanently shifted, duplicate & non-citizen voters, while ensuring that eligible citizens are not left out.

Source: Wikipedia — Special Intensive Revision (CC BY-SA 4.0)