DG must be an officer of minimum grade:

The grade of an officer indicates their seniority, experience, and the level of responsibility they are qualified to handle. For a position as significant as a Director General (DG), a high level of administrative experience and leadership is required. Therefore, the DG must typically be an officer of a minimum grade of BS-19. This Basic Scale (BS) grade signifies a senior management position, reflecting the extensive experience and expertise necessary to lead an authority effectively. Officers of lower grades like BS-17 or BS-18 would generally lack the requisite seniority and experience for such a demanding executive role, while BS-20 is a higher, but not necessarily minimum, grade.