sentences:  On 15 January 1973, he returned to Air Headquarters, designated as the new Chief of Air Staff, succeeding Air Chief Marshal PC Lal.Air Chief Marshal Mehra relinquished the post to Air Chief Marshal Hrushikesh Moolgavkar on 31 January 1976, on completion of his tenure.After his retirement, he represented India at a UNESCO meeting in Paris as deputy leader of India's team.