Hi @Abh1shekum
Index in itself is not a tradable instrument, so in reality there is no volume available for indices. TradingView shows volume summation of its individual constituents without any weightage.
We show all the prices, volume and OI as it is recieved from the exchange. We do not recieve any volume from exchange for indices.
But we have your feedback, we will figure out something on similar lines. By the way, you can track volume on futures chart at dhan and we have continuous chart so it may suffice your needs.
Hope this helps!