Termination of Job due to business reason of the company

I am working in a IT MNC company in Chennai. Now they have decided close our operations in this center by Sep 30 and the employees will be provided severance package. It is calculated as 4 Weeks salary for the 1st year and 2 weeks for the subsequent year. (If an employee has worked for 2 yrs, he will get a compensation of 6 weeks salary). My question in this scenario is as follows: - As the company has set a deadline for us as 30th Sep, If we decide to leave before Sep 30, are we still eligible for the Severance package? - Is it legal for the company force us to stay and work still 30th Sep to receive the severance? - In case if we decide to leave early, can the company force to serve the 30 notice period which we have signed during our offer? This queries arise as we didn't decide to quit the job. We are ready to work but they have decided to close this center for business reasons. As this is the case, does any of the above 3 queries violate the labour law in India? Kindly clarify on the same.