Fifteen Minute Candle Data for BANKNIFTY

[hrishikeshmurali]

I wish to get candle data (OHLC) aggregated over a 15 minute time interval (instant, not historical) for BANKNIFTY, without sampling and aggregating at my side. The historical API provides exactly what I need, but I need it for BANKNIFTY and it doesn't return anything even if I try. The documentation states that I can only get historical data for futures and not indexes. How do I get this?