NEW DELHI: Election Commission is contemplating a house-to-house verification exercise during the special summary revision of electoral rolls in Bihar ahead of assembly polls, aimed at not just adding eligible electors, but also deleting bogus entries, including foreign illegal immigrants erroneously included in the rolls.The last such rigorous roll revision – involving visits by booth-level officers to each house to verify the names for addition, change in existing particulars, and deletion of shifted and dead voters as also non-citizens possibly included on the basis of documents that may not conclusively prove their citizenship – was undertaken in 2004. “In the past, concerns have been raised by various civil society organisations, political parties and agencies regarding the inclusion or deletion of names of electors in electoral rolls,” a senior EC functionary told TOI on Sunday.