NSE's benchmark index tracking the 50 largest, most liquid Indian companies by free-float market capitalization.
The Nifty 50 is the National Stock Exchange of India's flagship index, made up of 50 of the largest and most actively traded companies across sectors — weighted by free-float market capitalization, meaning shares actually available for public trading rather than promoter or government holdings.
Because it's diversified across roughly 13 sectors (financials, IT, energy, FMCG, and more), the Nifty 50 is the most commonly quoted proxy for 'how the Indian stock market is doing,' and is the underlying for the country's most liquid index futures and options.
Example
When you hear 'the market fell 1%' on Indian financial news, it almost always means the Nifty 50 fell 1%.