Nowadays, the intensity of air pollution, due to the industries and automobiles, has been increasing continuously. Nitrogen oxides (NO X) are one of the most harmful pollutants, which are getting released from both automobile and stationary diesel engines. They essentially need to be removed from the exhaust using after treatment systems. However, the energy required to remove these pollutants is one of the major considerations in selecting the technology for pollutant removal from diesel engine exhaust. A study has been carried out on the non-thermal plasma-based NO X removal technique using various combinations of power supply units and electrode configurations. Three different electrode configurations are tested, in which two are cylindrical electrodes with diameters 3 and 5 mm, and the other one is a square electrode with a diagonal of 5 mm. A comparison is made between the results with two different pulse power supply units, PS-I: high-voltage direct current test set based and PS-II: DC-DC converter based. The square electrode with PS-II has been found to be the optimal combination, which has removed 85% of NO X from the exhaust at an energy density of 55.5 J/L, when the initial NO X concentration in the exhaust is 388 ppm.