This is because of disagreement about how emissions that cross region borders should be allocated: do they belong into the place of departure or state of origin? How are connecting flights accounted for? The tensions in achieving Intercontinental aviation and shipping discounts are discussed in detail inside the Carbon Transient https://landenmhgat.iyublog.com/29101761/how-much-you-need-to-expect-you-ll-pay-for-a-good-emissions-reporting