Shilpa,
They are the popular stock exchanges in world,
Sens*x refers to "Sensitivity Index" and is generally associated with the stock market indices. There are currently two major stock exchanges in India, The Bombay Stock exchange and The National Stock Exchange.
The S&P CNX Nifty ( Nifty 50 or simply Nifty) is a composite of the top 50 stocks listed on the National Stock Exchange (NSE), representing 24 different sectors of the economy. It is a simplified tool that helps investors and ordinary people alike, to understand what is happening in the stock market and by extension, the economy. If the Nifty Index performs well, it is a signal that companies in India are performing well and consequently that the country is doing well.
Pls refer the website of NSE & BSE for more information.
With best regards,
Sandip