Yes, withdraw your funds asap from these exchanges, because once RBI regulations start kicking in it'll be unclear how you could get your funds out. You will still probably be able to withdraw your funds in BTC, but I doubt that there will be demand for rupee balances stuck on these exchanges.
Didn't expect this to happen. Is there a link for an official statement regarding this?
Well, this has been announced ages ago by the RBI. So it's really expected by everyone, it's just that it's only coming into effect now.
It's important to note though that these regulations imposed by the RBI are only applicable to banks, and you are still able to trade bitcoin freely with other payment methods. I expect that p2p trading within India with various payment methods becoming a lot more popular following this announcement from major exchanges.