Hi Neha,
Back then, when someone pledge securities, it was moved to Broker’s pool account. With the revised SEBI circular dated Feb 25, 2020, the securities remain in the client demat, but a pledge is marked in favour of the broker (Trading Member ™) who in turn pledges to the Clearing Member (CM) and in turn with Clearing Corporation(CC). For this pledge to be marked, the customer will need to authenticate the transaction using an OTP. The details regarding the changes in Pledging and MTF are explained in this post.
You can check the below mentioned posts for further clarity.