No, you will not get any margin benefit for pledging the approved securities on the settlement holiday. In such a case, the margin benefit from a successful pledge request will be credited to the Jainam account only on the next trading day after the settlement holiday.

For example, if Thursday is a settlement holiday and a client has pledged his approved securities in Jainam for margin on Thursday, then the collateral margin will be received by him only on Friday.

To understand more, also see:

What is Trading Holiday and Settlement Holiday?

What is the impact of the settlement holiday

You can see the list of settlement holidays here.