CD Rewards is cashback earned when you shop on FLIPKART via CouponDunia.
This cashback is given the different name "CD Rewards" because Flipkart does not allow withdrawal of this cashback to a bank account.
The process for earning of CD Rewards is the same as CD Cashback. CD Rewards can be withdrawn to PayTM, used for mobile or DTH Recharge and converted to Flipkart Gift Card or Amazon Pay Voucher. In short, you can withdraw CD Rewards as you like, except to a bank account. This is why the balance available for bank transfer may be less than your total available balance.