The Election Commission of India (ECI) enrolls persons "ordinarily resident" in a constituency during voter enrollment.
According to the ECI,
a person is said to be ordinarily resident in a place if he uses that place for sleeping(Election Commission of India 1993).
For homeless persons, citizenship determination requires
specific information about the place of his birth and the place of previous residence.
The ECI instructs enrollment officers not to insist on documentary proof of age if a person
physically appears to be21 years old (Election Commission of India 2023: 48), and similar instructions apply to sex workers (Election Commission of India 2023: 43).
Author's summary: ECI enrolls citizens based on residency and appearance.