No benefit on Early Pay-in (EPI) of securities by non-POA clients will be given on settlement holiday. On settlement holidays, non-POA clients will not get EPI benefit/margin by doing early pay-in of securities, and therefore they have to maintain required margin for executing any sell order on settlement holiday.

To understand more, also see:

What is Trading Holiday and Settlement Holiday? and

What is the impact of the settlement holiday

You can see the list of settlement holidays here.