A letter written by BJP president Nitin Gadkari lobbying for contractors building a mega-dam project in Maharashtra has the Congress demanding his resignation, and the BJP on the defensive. NDTV disclosed in an exclusive report on Thursday that the in the letter written on July 30 to Water Resources Minister Pawan Kumar Bansal, Mr Gadkari asks for Rs. 400 crores to be released to the contractors hired for the Gosikhurd dam in Vidarbha.