Ipc

For that the first wife or her parents can file a private complaint in the court for bigamy, instead of filing a complaint in the police station.  She has to send a separate complaint to husband's employer asking to take departmental enquiry for gross misconduct.  If the charges proved, in the court case he will be imprisoned and in the departmental enquiry, he will be dismissed from the services.

If that first woman is of other caste like Muslim and that person is Hindu and they are not legally married, can that person's blood relative file a case and send a complaint to his department for departmental enquiry against that person if they want to ...

Regards,

Aniruddh

If the first marriage has not been solemnized in accordance with the law, then there is no case in the courts or in the department against that person.  If you are representing the first wife, then there are some options available to her in criminal law as well as for maintenance etc.