Hey @Other Stuff14,
Yes, as per the SEBI guidelines, you're required to keep 20% of funds as upfront margin in your trading account at the time of selling your holdings. However, if you do not keep the required balance, then at the time you sell your holdings, 80% of your amount would be released and 20% of the funds would get blocked. It would be released after T+2 days.
Hope this clarifies!