Rules for Holiday policy and leave policy and the difference between them?

Dear Seniors, Hello I am working in a Software Development firm as an HR Person. Till this time we never had any leave policy in our office, now the partners are deciding to adopt one, i proposed them that there should be minimum 21 days leave granted to the employees, however the top bosses are not agreeing to it and saying that the national holidays will be inclusive in the leave which comes to 16 days in a year and rest 5 days the staff can take the leave.
Would like to know is there any difference between the holiday and leaves and is the difference stated in any of the acts. Kindly let me know any rules there for holiday policy and leave policy , if there kindly share me those .This way the system is not beneficiary to the staff and is also not professional. This is creating a kind of demotivation among the staff. Please help me at the earliest.
Regards,
Divya

In nut shell, leave is employee centric and holiday is establishment centric which means leave is for employee and holiday is for establishment. On holiday, the establishment is shut officially as per law and though no employee is required to report for work on holiday, you cannot treat them to be on leave for that day because an employee remains absent from work not at his instance on holiday but at the instance of the management.
If he remains absent from work at his instance(as per his need)with the approval of the management, then he is said to be on leave.The number of leaves an employee enjoys in a year is stipulated by the relevant Shops Act or Factories Act and that is the minimum he is entitled to and it cannot be adjusted against holidays of the establishment despite the fact that the employee remains absent from duty in both the cases..
B.Saikumar
HR & Labour Relations Adviser
Navi Mumbai