First of all, you must determine what is the nature of leave.
Let me cite the Bombay Industrial Establishment (Standing Orders) Rules 1959. It provides a Model Standing Orders under Schedule I. Of which Section A deals with workmen dealing with manual or technical work and Section B deals with workmen employed on Clerical or Supervisory work. Rule 14 in Section A and Rule 16 in Section B deal with Casual Leave. Both contain 5 sub clauses and the provisions in both are identical. Therefore, i am just giving one set of rules here below:
16 (1) Every workman shall be entitled to casual leave.
16 (2) Casual leave shall be non cumulative and no leave of any kind may be combined with casual leave.
16 (3) Except for emergent reasons, casual leave shall be limited to three days at a time. Casual leave is intended to meet special or unforeseen circumstances for which provision cannot be made by exact rules.
16 (4) Holidays declared by the establishment and weekly holidays may be prefixed or suffixed to casual leave.
Now, please check for something similar enacted by the state government. You may refer to other acts like Factories Act etc depending on the nature of your establishment.
Hope this helps you to understand somewhat.