Dear Jay ji,
Yes. It is mandatory to give paid holiday on polling day - Parliament and State Assembly.
Kindly refer the Section 135B of the Representation of the People Act, 1951 which state as under:
1. Every person employed in any business trade, Industrial undertaking or any other establishment and entitled to vote at election to the House of the People or the Legislative Assembly of a State shall, on the day of poll, be granted a holiday.
2. No deduction or abatement of the wages of any such person shall be made on account of a holiday having been granted in accordance with sub-section (1) and if such person is employed on the basis that he would not ordinarily receive wages for such a day, he shall nonetheless be paid for such day the wages he would have drawn had not a holiday been granted to him on that day.
3. If an employer contravenes the provisions of sub-section (1) or subsection (2), then such employer shall be punishable with fine which may extend to five hundred rupees.
4. This section shall not apply to any elector whose absence may cause danger or substantial loss in respect of the employment in which he is engaged.
Danger or substantial loss is not defined any where.