Asking a female employee to resign after she has joined back from maternity leave

In the situation of the company not doing well and reduction of workforce is unavoidable, the principle of last to come, first to go shall apply. Other aspects are irrelevant.

What are the terms and conditions of your company at the time of issuing appointment orders?

Resignation should be voluntary. If forced, it amounts to illegal termination.

No employee can be forced to resign anytime.

That apart, under the Maternity Benefit Act, it is not permissible to terminate an employee when she is enjoying the maternity benefit.

If the matter is taken to court and you have sufficient proof that you have been forced to resign, then such forced resignation will be treated as wrongful termination.

The query itself smacks of malafide proposal.