Overtime

Hi Greetings for the day! My name is Bhanu Sharma. I work at a recruitment consulting based out of subhash nagar, New Delhi. The issue is the company is facing frequent powercuts these days and their generator backup is also not there to keep work ongoing. Today only we had a powercut at 11 AM then we were sent to some random training session which continued till 3 PM. At 3 PM the HR came and told us to go home as electricity issues were there. And COMMANDED the employees that work hours from 1 May till 6 May 2017 will be 9 AM to 7:30 PM. My general shift hours are 9:30 AM to 6:30 PM. She ended her statement saying either you all will be coming at 9 to 7:30 slot or else you leave the organisation.No employee is happy with this. I just wish to know if we being an employee can do anything in regard with this. And ask for any overtime compensation too for that. What are the related laws which can help me raise a word against this situation. Regards Miss Bhanu Sharma