Market Capitalisation of BSE

Can you just tell the exact amount of market capitalization of BSE in 1978-79?

The Base value for Sensex in '79 was 100. By the way, when Sensex started, it was not really free-float market capitalization. It was market cap weighted. You can read more about Index here.

The index points are not impacted when BSE (or NSE) adds or removes a company from the index.