"We have decided to not permit use of HDFC Bank credit, debit and prepaid cards towards purchase or trading of bitcoins, cryptocurrencies and virtual currencies, on merchants suspected to be dealing in crypto-currency or online foreign exchange trading or both," the bank said.
"Government does not consider crypto-currencies legal tender or coins and will take all measures to eliminate the use of these crypto-assets in financing illegitimate activities or as part of the payment system," he had said.
[1] https://economictimes.indiatimes.com/industry/banking/finance/banking/hdfc-bank-blocks-all-its-cards-to-buy/trade-cryptocurrencies/articleshow/63290070.cms
http://www.livemint.com/Industry/w6hbySinYCSUUURkrasUCL/HDFC-Bank-blocks-all-its-cards-to-buy-trade-cryptocurrencie.html