If employees are required to work on a Sunday, the following is the requirement as per the Factories Act, 1948:
Section 52 in The Factories Act, 1948
52 Weekly holidays
(1) No adult worker shall be required or allowed to work in a factory on the first day of the week (hereinafter referred to as the said day), unless—
(a) he has or will have a holiday for a whole day on one of the three days immediately before or after the said day, and
(b) the manager of the factory has, before the said day or the substituted day under clause (a), whichever is earlier—
(i) delivered a notice at the office of the Inspector of his intention to require the worker to work on the said day and of the day which is to be substituted, and
(ii) displayed a notice to that effect in the factory:
Provided that no substitution shall be made which will result in any worker working for more than ten days consecutively without a holiday for a whole day.
(2) Notices given under subsection (1) may be cancelled by a notice delivered at the office of the Inspector and a notice displayed in the factory not later than the day before the said day or the holiday to be cancelled, whichever is earlier.
(3) Where, in accordance with the provisions of subsection (1), any worker works on the said day and has had a holiday on one of the three days immediately before it, that said day shall, for the purpose of calculating his weekly hours of work, be included in the preceding week.