3. Every employee shall be entitled to and be granted holiday with wages on every national holiday ; anything contained in any other law, contract, document, usage or practice to the contrary notwithstanding ;
Provided that where an employee is, for any exigencies of business of the industrial establishment, required to work, and works on a national holiday, he shall be paid by the employer, twice the wages for a day, or at the option of the employee, wages for that day, and also a substituted holiday with wages falling within the next calendar month, not being a weekly holiday.
Explanation — Where an employee is paid wages by the day, or at piece rates, his wages for a day payable to him under this section, shall be the daily average of his wages, to be calculated in the manner prescribed.