What is Cross Margin and why is it being introduced?

Updated 

Cross margin is a margin preference where the locked margin for all cross positions and open orders, Futures wallet balance, and unrealised PNL of cross positions collectively serve as the margin pool for all cross positions. This allows the users to make an efficient use of margin and better manage the risk. However, in case of liquidations while trading in cross margin, the users can end up losing their entire Futures Wallet balance.