"Unko sharab yaad aana swabhavik hai (It is natural for him to remember liquor)," Modi said tongue-in-cheek in the Lok Sabha without taking the name of the Congress leader.
The Prime Minister's remarks came during his speech on the Motion of Thanks on the President's Address.
Earlier in the day, Singh had described BJP government's agenda as "old wine in new bottle" while saying that almost all the issues raised were "the same programmes started by the Congress earlier which have been brought in now with new names.