The main objective of this research paper is to perform a parametric comparison of gas flow (air and hydrogen) through a curved channel in terms of thermodynamic based environmental and sustainability analysis. For this analysis, the following sustainability indicators which are i) exergetic efficiency (ee), ii) waste exergy ratio (wer), iii) environmental effect factor (eef) and iv) exergetic sustainability index (esi) are defined and estimated in terms of the channel aspect ratio (AR), Dean Number (De) and reference temperature (T-0). Consequently, it is found that ee and esi rise with the increment of De and AR of the curved channel and with the decrease of T-0. However, wer and eef show the opposite behavior. As an important conclusion, air flow through the channel is found to be more exergetic than that of hydrogen under the boundary conditions assumed for the problem. The ee and esi increases with the rise of De while rising with the decrement of T-0. For air, maximum ee and esi values are obtained to be 99.9% and 751.69 incase De is 207.1 and T-0 is 243 K. Adding that, for hydrogen, the maximum ee and esi values have been estimated to be 99.8% and 710.5 while De is 202.3 and T-0 is 243 K. The ee and esi increase with the rise of AR. For air, the maximum ee and esi values are found to be 97.9% and 45.8 while De is equal to 207.1 and AR is 5.5. Also, for hydrogen, the maximum ee and esi values have been calculated to be 97.5% and 38.6 while De is 202.3 and AR is 5.5. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.