• Company not giving the entitled leaves. Can I file a law suit?

Hello,
My sister has been working for a very nice company in noida for last 8 months. But whenever she wants a leave for herself or want to take a day off, her Team Lead doesn't approve the holiday. He asks for document supporting the leave. Even when its 1.25 days per month entitlement for the leaves. because of this she is not able to get even a day off work and if she takes a leave they put it in unscheduled leave and cut the salary for the day.
What documents can a person possibly present when they are just visiting there ancestral place which is just 20km away or just want to take a day off from work. Couldn't understand. What legal action can I take against that company?