Bank Nifty has now broken in 9937 low, which corresponds to 5170, so it seems that the Bank Nifty is trying to lead this decline. If I have to choose between going short with either of the index, I would go short with the Bank Nifty than with the Nifty, just as a comparative. But yes, if 5170 starts getting decisively broken, then obviously you have to push the short side.
