Hon’ble Madras High Court held that after the introduction of the concept of “block of assets”, depreciation is allowable with reference to the block of assets and not with reference to each individual asset comprised therein. On and from 01.04.1999, depreciation is granted in respect of business assets, tangible or intangible, falling within the relevant block and the question of attributing a specific asset to a particular unit does not arise. Thus, once an asset forms part of a block of assets, its individual identity is lost for the purpose of depreciation. As long as the assessee continues to carry on business and the block of assets is put to use, depreciation is allowable on the entire block irrespective of whether a particular asset within that block remained unused during the relevant year.