DP transaction charges
Demat transaction charges are Rs. 13 plus Rs. 5.50/ - (CDSL Charges) per scrip exclusive of taxes.
The CDSL & NSDL are the depositories that charge the DP charges as a source of their revenue. Depository Participant charge is levied any time you sell shares from your demat account. This is akin to Exchanges like BSE and NSE charging a transaction fee.