The Congress has demanded a CBI inquiry into Dumper scam in Madhya Pradesh. The party MPs belonging to the state today sat on a dharna outside Parliament House carrying placards demanding sacking of the state Chief Minister Shivraj Chauhan for alleged corrupt practices. Mr. Shivraj Singh Chouhan's wife Sadhana Singh is alleged to have bought allegedly dumpers or special trucks and leased them out to a cement factory. The Chief Minister's wife at the time of purchased named her husband as SR Singh and gave a false residential address.