Gadkari said the deal was done at a hotel in Delhi.
He said the main issue of the deal was to prevent the BJP from coming to power.
"An industrialist had struck the deal between Arvind Kejriwal and the Congress in a five-star hotel here...whatever their leaders ate and talked about was revealed by a person to me," Gadkari said at a function here.
"The mediator told me that the only point in the meeting was to stop the BJP from coming to power in Delhi," he said.
Creating history and scripting a new political discourse for India mired by graft and show of pomp by leaders, Kejriwal on Saturday took oath as the seventh and youngest chief minister of Delhi in the open Ramlila Maidan, promising a common people's government in true sense and pledging to root out corruption.
In his swearing-in speech, 45-year-old Arvind Kejriwal, who and his team came to take oath in metro trains shunning the trappings of VIP culture, said it is the people of Delhi who will run the government in the national capital now on.
After days of a stalemate in Delhi over government formation since no party got absolute majority, the AAP on Dec 23 said it will form the government with the support of the Congress party.
The just-over-a-year-old party led by Kejriwal emerged as the second biggest outfit with 28 seats, falling only a few seats short of the right wing BJP and allies who managed 32 seats.
The BJP is four short of a majority in the 70-member Delhi assembly. Congress managed only 8 seats.
--IBNS (Posted on 28-12-2013)