The problem with the market is highs are rare and lows are common. You might get negative returns if markets are low at the time when you need money. So only if you have staying power (ability to wait) should you enter the equity market OR invest and forget only extra cash. How many of us have extra cash? As far as I am concerned I believe in cash is king.
If you kept 1,00,000 rupees in a saving banks account you will get Rs 4000/- as annual interest which is totally exempt from tax. After 12 years it will become 1,60,302 rupees.
This money is pure money, can be used for any purpose howsoever you want. Whether it has lost more value or less value only time will tell. But better than investing in dud stocks, dud financial companies, chit funds and ponzi-like schemes. Many reputed mutual funds have given equal or worst returns than the example mentioned above.