(5)The technical screening criteria for determining whether an economic activity contributes substantially to climate change mitigation or climate change adaptation and does no significant harm to any of the environmental objectives should build, where relevant, on existing Union law, best practices, standards and methodologies, as well as on well-established standards, practices and methodologies developed by internationally reputed public entities. Where objectively there are no viable alternatives for a specific policy area, the technical screening criteria could also build on well-established standards developed by internationally reputed private bodies.