If you have bought the share and it touched the lower circuit, you may not be able to square off. Because there will be only sellers and no buyers. In this case you will have to take delivery. This is not that bad. But if you have done shortselling and the scrip touched upper circuit then there will only be buyers and no sellers. If you have the stock in your account then ok otherwise you will face difficulty. It will go for auction settlement and you will have pay nearly 20% extra as penalty and other charges.