Permission For 24 Hours Working - Call Center

Hi,
First of all i apologize if i have posted in the wrong section or category, now to the question that i have,i run a small call center operations for a USA based client so we are required to work during night (9PMto 8AM),I have set up my call center in south Delhi(rented out the space in a commercial area with rent agreement) and our company is registered as sole proprietor ship in Delhi with current account and everything,now my question do i need any special permission to work in the night hours and if yes what would be exact procedure i need to follow to get this license?
NOTE:please provide all the information in detail
Thank you for all the help in advance.

Dear Rahul Sharma,
I recommend you visiting the labour office of your area and talk to the labour officer. He is the right person to guide you.
At the end of the post, you have placed a note that says "Please provide all the information in detail". Well gentleman, please note that we are not paid consultants. Members of this forum have their own limitation in providing specific information. Therefore, there are limits on how much to expect from the members of the general forum. Secondly, these statements are suitable for the employees working for you and not for the members of the general HR forum. I strongly recommend you distinguishing this fact.
All the best!
Dinesh Divekar