Amazon is now part of Payback loyalty programme. You can get 6 points for every Rs. 100 spent on your Amazon account. If you are already a Payback customer, you can redeem your Payback points for the purchases made on Amazon.
On the Check out page, give your Payback account number and verify the same with your secret PIN.
As mentioned earlier Payback joined amazon.in as a store partner. And you can spend around 100 Rs and earn 6 points. Do note that the points from which you wish to shop back at amazon requires a lot of stored points. So the things to be purchased with payback don't come in cheap.
Some of the amazon.in store specific rewards are listed on this page: http://rewards.payback.in/
If you choose to use the above page your amazon account can recognize the payback points and use it during checkout page.