The law is well settled that a person who claims exemption or concession has to establish that he is entitled to that exemption or concession. A provision providing for an exemption, concession or exception, as the case may be, has to be construed strictly with certain exceptions depending upon the settings on which the provision has been placed in the statute and the object and purpose to be achieved. If exemption is available on complying with certain conditions, the conditions have to be complied with. The mandatory requirements of those conditions must be obeyed or fulfilled exactly, though at times, some latitude can be shown, if there is a failure to comply with some requirements which are directory in nature, the non-compliance of which would not affect the essence or substance of the notification granting exemption