Sir,
Does SELL/exit/close/square off in index option buying (NIFTY, FINNIFTY, BANK NIFTY) need margin
When you’re trading, you have the choice to go either long or short. This involves two actions: entering the position and exiting it. If you’re considering shorting or writing options as your initial move, then yes, margins will be necessary.
You can check on this link to understand the concept of margins.