Mahadalit is a term used to refer to the marginalised sections among the Scheduled Castes of Bihar.
The Nitish Kumar led NDA government in Bihar set up the State Mahadalit Commission in the year 2007 to recommended inclusion of extremely weaker castes amongst the Scheduled Castes and as per the commission's reports 21 castes have been categorised as Mahadalits.
During the election year of 2010, Nitish Kumar launched a slew of government schemes to woo mahadalit voters. Nitish said, "My aim is to see the social, economic and political growth of certain castes who need a special campaign for their overall development." The Mahadalit status entails benefits of over a dozen government welfare schemes including free land to the landless.
References
Mahadalit Wikipedia(Text) CC BY-SA