RSI is a momentum oscillator
The Relative Strength Index compares recent upward and downward price movement on a bounded scale. It is commonly used to describe momentum, not to predict a guaranteed reversal.
In a strong trend, RSI can remain elevated or depressed for longer than expected. Treat the reading as context and define what price action would confirm or invalidate your idea.
A practical RSI workflow
Begin with the price chart and mark the relevant support, resistance, and session levels. Then use RSI to ask whether momentum confirms the move, weakens while price extends, or changes regime.
For NIFTY and BANKNIFTY, compare the same RSI settings across timeframes instead of changing parameters until the historical chart looks attractive. Test any strategy on representative data before relying on it.