Unless otherwise specifically requested for regulatory purposes, all Buckets should be created within the region europe-west1 and all datasets within BigQuery should be created in the multi-region EU.
In the event that it is not possible to use these regions, special considerations and exceptions must be made for any data flows; as within BigQuery it is not possible to query two tables that are physically present in two different regions.
Bucket localization is managed on the project level by the Cloud Operations team.
Dataset localization must be managed by the Data Engineering and Data Architecture team.
Costs
Keeping data within the save regions saves or completely reduces the costs when transferring data between services. As a result, this rule must be respected whenever possible.