The Election Commission has issued instructions mandating new applicants seeking inclusion in the voter list to submit their parents' SIR details along with the Form 6, according to officials.
The declaration was added in the Bihar SIR rolled out in June last year.
According to officials, the declaration was added through instructions and the Form 6 has not been amended. New voters were made to file the declaration along with Form 6.
"Daily SIR bulletins of Bihar showed the form filled along with declarations," an EC functionary said.
"It helps in mapping electors and reduces the documents new voters need to submit along with the application," the official added.
If a person fills Form 6 online, he or she cannot proceed further till the declaration is filled.
Separately, the poll authority has defended the Special Intensive Revision (SIR) of electoral rolls, rejecting concerns raised by UN rapporteurs and asserting that the process is transparent, constitutional and endorsed by the Supreme Court.
EC officials said the SIR aims to include all eligible Indian citizens while removing duplicate, deceased, shifted, absent and foreign voters from electoral rolls.
Responding to allegations of large-scale deletion of minority voters, including in Nandigram, West Bengal, EC officials said voters had adequate opportunities to challenge exclusions and denied any bias.
In a recent letter to the government, UN Special Rapporteurs have raised concerns over the SIR, alleging that the process lacks transparency.
(With inputs from PTI)