Aerodynamic performance of a turbine stage is influenced by the losses occurring within individual turbine blade rows. Total pressure losses within a turbine stage are classified into primary, secondary and annular wall losses. Primary losses are further divided into losses due to shocks and momentum deficit. In turbomachinery design, it is a standard methodology to discretize blades of stator and rotor rows into several airfoil sections during their respective blade design process. The aim of the present paper is to put forth the airfoil redesign methodology adopted in arriving at an improved airfoil of mean section of a baseline axial turbine Nozzle Guide Vane of an existing low-pressure turbine stage at the Versatile Turbine Test Rig (VTTR) at Propulsion Division, CSIR-NAL. Baseline airfoil is characterized for aerodynamic performance using RANS CFD simulation and flow field is analyzed in detail. Details of the numerical setup, grid dependence and turbulence model are furnished in the paper. It is observed that high flow accelerations over the suction surface are causing an early and drastic rise in loss at onset of transonic flow. Sensitivity study of Unguided turning (UGT) and Trailing Edge Wedge Angle (TEW) is carried out using 2D CFD to generate a population of airfoils and shortlist Six airfoil designs for detailed 3D CFD analysis. It is found that use of a flat back suction surface with a suitable combination of trailing edge wedge angle. The redesigned airfoil referred to as “Profile 5” in the study achieves a reduction of loss by around 40% compared to that of baseline airfoil at the design point condition of Exit Mach Number M = 1.