It's simply because of supply and demand, speculation.
Buyers are willing to pay whatever the sellers are asking and now you also have to put the banking restrictions into the mix. Higher demand, limited options, definitely premium. Yeah, things might change as adoption increases (more supply) and more options (regulations).
The premium was there even when there were no banking restrictions.
While the demand for digital assets in quite robust in India, I refuse to accept that the supply is low. India has the second highest Blockchain developer base. We have so many bounty hunters and all of these (Developers and Hunters) are paid in Cryptocurrency. I guess that India has a fair share of cryptocurrency holding with its population.