@ShubhS9 , currently the margin for shorting 18100 ce is 93k , will it increase to double times near expiry ie on wednesday & thursday to 1.8 L as like stocks or it is only for physically settled stocks and not for indices ?
Index F&O are cash-settled. So there is no requirement for additional margin. Even for Stock Futures and Short Option positions, the margin will increase to 40% of the contract value or SPAN + Exposure margin (whichever is higher) on expiry day. Please check out this post for more information: Relaxation in Physical Delivery Policy - Margins collected