The Election Commission (EC) on Tuesday served show-cause notices on law minister Salman Khurshid and his wife, Louise Khurshid, Congress candidate from Farrukhabad in UP, over his promise of a 9% sub-quota for backward Muslims within the 27% quota for OBCs.
UP chief electoral officer Umesh Sinha said the notice was served for violating the model code of conduct.
AK Lal, returning officer for Farrukhabad, said he had sought a reply within three days from Louise Khurshid.
Khurshid said there was no law against promising more quota and he was only referring to his party's election manifesto.
The Congress refused to comment amid talk that the party was looking to consolidate its base among Muslims, having earlier announced a 4.5% sub-quota for minorities within the OBC quota.
The BJP complained against Khurshid to the poll panel while the Samajwadi Party accused the Congress of deceiving people.