Concept of block of asset

in Block of Asset concept assets loose their individual identity and depreciation is accounted on the balance of the block as at the year end.

The depreciation should be calculated on 726021, and no further treatment is required untill and unless either no asset is left in the block or where sale consideration of any or all assets in the block exceeds the WDV of the Block.

In this Case there will not be any special treatment, The Block of asset shall continue to exist and Deprecaition shall be charged on the Balance of Block for the whole year at the applicable rate. No treatment for the amont of loss being incurred. Also the assesse has option to pay tax on presumptive basis u/s 44AE of Income Tax Act.

as per income tax act WDV is calculated in following way, 

opening wdv- sale of asset + purchase of asset is the net block of wdv on which depreciation is to be calculated.

in your case u have to calculate on 726021 only