Leave Policy for Kolkata - Are there any laws and rules that we have to follow or can define our own?

Hello, We are starting a small software development company. We are recruiting new employees. Hence, we would need to define PL, CL, SL, and Maternity leave as part of our leave policy. Our company is based out of Kolkata, West Bengal. Understand some big software companies do not have CL also.
Are there any laws and rules that we have to follow or can define our own leave policy
Would request kind advice
Thanks

Please go through the leave provisions under the West Bengal Shops & Estts Act which is applicable to your establishment.

Kindly refer Section 11 of West Bengal Shops and Establishments Act_ 1963, Attached the particular section for your reference.