The data is representative as far as any data publicly available is representative of South Asia.
I care about data, not what BSP stands for. Whether you look at British census figures or modern Indian figures, there is no way Dalits are remotely close to a majority anywhere.
Indus Valley is those regions primarily watered by the Indus and speak Northwestern Indo-Aryan languages. Pretty simple. Haryana wasn't included as there isn't good data for the area, and its basically just a mixture of Punjabis and Gangetic groups.