Why the controversy over Pinga song?

The Ranveer Singh and Deepika Padukone starrer “Bajirao-Mastani”, produced and directed by Sanjay Leela Bhansali, has landed into controversy, with the descendant of Bajirao Peshwa I alleging that historical facts have been “altered” while portraying the late king and his wives Kashibai and Mastani in the film. The 'Pinga' dance form is an integral part of Marathi culture and has been transformed into a 'item song' and the costumes and dance direction are on that lines, which has further add to the trouble of makers.