(c)A government servant declared by the committee to be completely and permanently incapacitated may, in special cases, be granted leave, or an extension of leave, not exceeding six months as debited against the leave account (where such an account is maintained for the government servant), if such leave be due to him. Special circumstances justifying such treatment may be held to exist when the government servant's breakdown in health has been caused in and by government service, or when the government servant has taken a comparatively small amount of leave during his service or will complete at an early, date an additional year's service for pension.