What is the total number of working hours as per Indian labour law?

I am working in an organization as a contratual Employee for 3 years In a semi govement organization that is hotel corporation of India .I want to know that what is the working hour in a week according to indian Labour law. As we have Morning shift of 8 hrs Afternoon Shift of 7 hrs and night shift of 10 hours in that in a week i have to go 3 days morning 1 afternoon and 2 night then off in total i work 51 hours a week .so pls advice me what action can be taken because in a month i am given 12 hours extra to company and not getting any off extra or any money for the same .So please tell me what action can be taken so that either i get a 9 hours fixed shift or 12 *24 shift or i should get paid for that extra hours looking forward from your side thanks Bineet