NEW DELHI: National Commission for Scheduled Castes (NCSC) vice-chairman Arun Halder on Thursday said cases of atrocities against Dalits are on the rise in Tamil Nadu and accused the state government of not taking any action. He said the NCSC has written to TN government to take suo motu cognizance of a DMK leader allegedly verbally abusing a Dalit youth for entering a temple, and has sought an action taken report.