This might be due to the pressure put by Indian government. It may be due to following reasons:
1) Government tried to prevent tax evasion by sending notices to Bitcoin investors. But a lot of people might be using KYC of other people like their servants.
2) It is hard to shut down the exchanges til proper laws are made regarding this. At such, suspending their bank accounts is only way to stop these exchanges.
If you use the KYC documents of your servants, it is a case of downright fraud. There is a paper trail and if your servant gets a IT notice, you know where the trail will lead to. There are strict laws against Benami transactions.
If the government decides to shut down exchanges, they can do so easily through a notification. They would not want to be hasty in passing laws, especially in a complex area like cryptocurrencies, but they still have the ability to shut down exchanges.
A few years back, raids from the ED resulted in exchanges being shut down.
https://www.theverge.com/2013/12/27/5248942/indian-feds-raid-bitcoin-exchange-as-other-traders-suspend-servicehttp://www.thehindu.com/business/Industry/bitcoin-exchanges-shut-shop-in-india/article5504407.eceThis bit of news is significant and as many have stated before me, I would expect Benson and representatives of other exchanges to comment on it. There is nothing on the Coinsecure blog as well...