OT Payment In India And Pakistan

Please could you provide me the information of mandatory overtime payment in India and Pakistan required by the Labour Law and the Labour laws governing OT. Help me understand this for an engineering company.
Seniors your quick help is highly appreciated, I have to make a business proposal for a new venture in India and Pakistan
Regards
Swapneel

Dear Peer,
Thanks for taking out time to respond to the same. I had already visited the site but it gave me a general overview. I want information in detail
1.Consider a engineering company which needs to be put up in India will engineers working in the same be eligible for OT.
2. What will be the basis of calculation.
Do workers get some extra perk other than OT if they work on a holiday.
Regards
Swapneel