How can people build ₹10 crore corpus for retirement if they begin investing at 40?

People starting at 40 can target a ₹10 crore retirement corpus by investing around ₹1 lakh every month in an SIP for 20 years, assuming an annual return of 12%. This is over three times the monthly investment needed by someone starting at 30. A 30-year-old would need to invest around ₹28,329 per month for the same target.