Open Interest is the number of SENSEX option contracts that are still open — written but not yet closed out or settled. This page plots call and put OI at every strike on the BSE SENSEX chain, alongside the change in OI. Rising OI at a strike means fresh positions are being built there; falling OI means positions are being unwound. The strikes carrying the heaviest call OI are commonly watched as resistance and the heaviest put OI as support.
SENSEX is the BSE benchmark of 30 large-cap stocks, and unlike the NIFTY family its options trade on BSE rather than NSE. OI tells you where positions sit, not which way price will go, so read it with the SENSEX Put Call Ratio for net sentiment, the max pain strike for the expiry-day magnet, and the option chain for the strike-by-strike detail. All three are linked above.