Google Play gift cards started appearing initially in the U.S. in the year 2012. From then, the program was gradually rolled out to the other markets. Now, it looks like India is the next country to receive the Google Play gifts cards.
Google has updated its support pages listing the India specific terms. However, these are not available for purchase right now. The page shows specific gift cards entry for India, but it states that the retail partners are coming soon. Perhaps, it will be available from all the usual sellers of the tech products in India.
From this page, we know that the cards will come in different price points such as 500 INR, 1000 INR and 1500 INR denominations. It should not be too long until the cards start arriving in India. There are chances for the gift cards to show up in some shops before Google updates its pages.