As per the direction of the election commission of India,all establishment, shops including those which work on shift basis shall be closed on the day of poll in the constituency where general election to be held. In case where a person ordinarily resident of the constituency and registered as an elector , may be serving / employed in industrial undertaking or an establishment located out side the constituency , having a general /by election even those workers including casual workers working outside the constituency concerned would be entitled to the benefit of a paid holiday extended under section 135B (1) Representation of the people act1951.
So your entitled for a paid leave on 16-05-2016.
However you say you are leave is rejected due to work requirement.Law apart Please keep in mind you will have to report back to your Manager.....