Post facto permission

CCS(Condcut) rules are available at

https://dopt.gov.in/sites/default/files/CCS_Conduct_Rules_1964_Updated_27Feb15_0.pdf

Rule 23. Interpretation

If any question arises relating to the interpretation of these rules, it shall be referred to the

Government whose decision thereon shall be final.

DOPT circular is available at

https://documents.doptcirculars.nic.in/D2/D02est/130_54-Ests-A-11-28021955.pdf

Denial of being considered for promotion could be challenged in a judicial review so that the question of law, if any, could be settled.

The challenge may be difficult aslong as permission (prior or expost facto) for continuing studies is not there.  without this the degree is not added to service record.