In administrative law, the distinction between 'mandatory' and 'directory' provisions of a statute determines: 

The distinction between mandatory and directory provisions is crucial in administrative law because it determines the consequence of non-compliance. If a provision is mandatory, non-compliance renders the action taken void or a nullity-the action has no legal effect. If the provision is directory, non-compliance makes the action irregular but not void-the defect may be cured or condoned. The Supreme Court in State of U.P. v. Baburam Upadhya (1961) laid down several tests for this classification: the language used ('shall' is generally mandatory but not always), the purpose of the provision, whether it is the essence of the thing required to be done, and whether non-compliance defeats the object of the enactment. The consequence of the distinction is significant-a void act confers no rights, while an irregular act may be rectifiable.