(b)in every other case, a Manager's Certificate not restricted to opencast mines only or a Degree or Diploma in Mining or Mining Engineering recognised by the Central Government: Provided that where special conditions exist, the Chief Inspector may, by an order in writing and subject to such conditions as he may specify therein, permit or require the appointment of a ventilation officer in variance of these provisions or require the appointment of such number of persons to assist the ventilation officer, as may be specified in the order:
