if wife applied

An employee must always request for his transfer, and the other party, who ever it may be becomes a stranger to employer.  No one can seek for transfer of others in writing officially.  Personal representations may be different.

this action will render you liable fo disciplinary action and almost life long guarantee of you not being posted to Kolkatta.

There are some instructions which serve only as guiding prnciples and not binding and not enforeceable through court which deal with the subject.

If your PSU does not follow the same then you have no choice.