The constitution makers were of the opinion that people from the oppressed sections of the society should be given some leverage so that they could enhance their political representation. They made the provision for reserved constituencies for members of the scheduled castes and scheduled tribes. As on 1st September 2012, there are 84 seats reserved for the Scheduled Castes and 47 seats reserved for the Scheduled Tribes
This has been done because in an open competition, these sections may not have a good and fair chance. They may not have resources like enough money for education etc and contacts to win elections.