See how long a corpus lasts if you withdraw a fixed amount every month while the rest stays invested.
Each month: balance = balance × (1 + i) − W, until the balance reaches zero. i = (1 + R/100)^(1/12) − 1, so with no withdrawals the result equals the lumpsum value.
₹10 lakh at 6% with ₹20,000 a month lasts about 5 years.