Worth keeping in mind that "emissions" targeted are actually somewhat localised. The initiatives are about reducing NOx emissions within the bounds of suburban

Worth keeping in mind that "emissions" targeted are actually somewhat localised. The initiatives are about reducing NOx emissions within the bounds of suburban areas, where it tends to become photochemical smog[0]. Yes CO2 is an issue, but a different issue, and frustratingly, thermal efficiency is correlated with NOx emissions[1], which is why we have these scandals coming up in the first place. [0] https://en.wikipedia.org/wiki/Smog#Photochemical_smog https://en.wikipedia.org/wiki/Smog#Photochemical_smog [1]https://www.alentecinc.com/papers/NOx/The%20formation%20of%20NOx_files/The%20formation%20of%20NOx.htm https://www.alentecinc.com/papers/NOx/The%20formation%20of%2... Edit: Worth clarifying that thermal efficiency and combustion temperature are also correlated, which is not plainly stated in [1]