For generations we had used 'Rs.' for displaying prices everywhere. There was no "symbol" for the Indian currency, the Indian Rupee, until 2010 that is. That's when the new '₹' symbol for the Rupee was finally declared, officially, to be the symbol for the Indian Rupee. However, the other nations that use the Rupee for their currency (like Pakistan, Sri Lanka, Nepal to name a few) still use the 'Rs.' to specify the currency unit.
For Windows users, you can go over to the Microsoft download website to get the update. Link
After the update and reboot, you can start using the new symbol with the "Ctrl+Alt+4" combination.