Hi @Nagasahitya, sorry for the delay in response!
Yes, CUSPA charges are applicable when equity shares are purchased using collateral margin, which results in a negative ledger balance and transfer of shares to the CUSPA account. This process incurs pledge charges.
When you later add funds or sell shares, thereby making your ledger balance positive, the shares are transferred back to your demat account, triggering unpledge charges.
You can read more about how the CUSPA process works in the post linked below: