On 16 April the Commission published a final rule to harmonise the start of the gas day in markets across the eastern seaboard from 2021. The new gas day rule will apply across different facilitated markets governed by the National Gas Rules. Under the final rule the gas day in each market location will start at 6am Australian Eastern Standard Time. Different gas markets across the east coast currently operate with different gas day start times as a result of legacy pipeline arrangements. These differences impose a cost on the increasingly integrated system.