CO & BO for Bank nifty Option

Can any one say when i place order bank nifty option by CO & BO type, Below message i m getting.
RMS:Blocked for BANKNIFTY OPTIDX nse_fo BO Remarks: BO are blocked for Banknifty Options block type: ALL

You cannot place bracket and cover orders for Bank Nifty options but you can continue to place MIS orders. We have blocked BO and CO orders due to exchange mandated open interest limits.

Thank You! thanks for information.

_Please advise , Bank Nifty Option Trade buy or Sell
in Cover order is possible _

Are Bracket orders allowed for Nifty options? If yes, then what is the leverage for buying and short selling Nifty options?