Six Indian stocks, including Bharat Heavy Electricals, Delta Corp, Gujarat Narmada Valley Fertilizers and Chemicals, Manappuram Finance, Canara Bank and Punjab National Bank, have been placed under a futures and options (F&O) trade ban. The F&O contracts of a stock are placed in this ban period when the open interest on it is higher than 95% of the market-wide position limits or MWPL. The ban continues until the open interest falls below 80%.