This is not a ban on cryptocurrency, just a restriction on banking services available to crypto-related businesses. It's not like Bitcoin is illegal in India.
Some Indian exchanges are already trying to bypass the ruling by offering P2P trading solutions + there's still Indian LocalBitcoins available.

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Meanwhile:

Indian Police Seek to Sell Crypto and Bypass RBI Ban
India's Ruling Party Accused of Involvement in 'Mega Bitcoin Scam'