Option chain

Option chains provide specific data related to options contracts, including strike prices, expiration dates, implied volatility, and open interest. Traders use this data to construct options strategies, manage risk, and profit from price movements in the underlying asset.
NSE's online Real time Data Feed. NSE's real time data is provided in various levels (level 1, level 2, level 3 and tick by tick) across segments such as Capital Market, Futures & Options, Currency Derivative and Wholesale Debt Market.

Nifty option chain is considered to be the best advance warning system of sharp moves or break outs in the index.