Intrinsic value of any asset is the present value of its future free cashflows discounted at an appropriate discount rate. The appropriate discount rate should be the realistic return that one expects from investing in that asset. Such expectation is shaped by returns on risk free instruments of similar maturity.
An equity share is a long dated asset, good ones are perpetual. Many great companies are in existence for over 100 years (For eg. Coca Cola, Unilever, P&G etc). In India, the longest dated risk free instrument is the 30 year government bonds. Their current (2024) yields are 7%. Given that equities are riskier and longer dated than this, we need to add some spread to this. Indian equity discount rates, thus, should be above 7% currently, but how much above is a matter of judgement.
Financial theory tries to use past volatility to arrive at this number and involves needless mathematical jugglery. We use a 10% discount rate for quality businesses and keep raising this for lesser ones. Mind you, present values are very sensitive to discount rates. A fall of 1% in discount rates, raises the present value of a 30 year cashflow stream growing at 5% annually by around 11%-13%. Without mathematical acrobatics, our practice is to use a high discount rate. If the business looks fairly valued leave alone cheap at that rate, we become interested.