It is the minimum acceptable value of the Net Liquidation Value% in your account. If the NLV % falls below this value then your account may get deactivated for taking further positions, however you will be allowed to square off your existing open positions.
If the NLV % falls below this value then AxisDirect shall have the right but not the obligation to square off all or some of the open positions so that the NLV % is restored to 100% or above.