The regulation on the establishment of a framework to facilitate sustainable investment aims to inform investors on whether an economic activity is environmentally sustainable by setting common EU-wide criteria.1 The regulation sets out the following criteria to be applied to decide whether an economic activity is environmentally sustainable: (i) contributes substantially to one or more of the environmental objectives; (ii) does not significantly harm any of these environmental objectives (climate change mitigation or adaptation, sustainable use and protection of water and marine resources, transition to a circular economy, pollution prevention and control, protection and restoration of biodiversity and ecosystems); (iii) is carried out in compliance with the minimum safeguards set out in the regulation; and (iv) complies with technical screening criteria set up by the European Commission in accordance with the regulation. In 2022, Austria initiated a case (T-625/22) against the Commission classifying nuclear and fossil gas activities as ‘sustainable’ for purposes of Regulation (EU) 2020/852.2 Austria argued that classifying nuclear and fossil gas as sustainable was a violation of the “Do No Significant Harm” principle, the precautionary principle, and exceeded the delegated powers of the Commission under Article 290 TFEU. The outcome, still pending, may have a decisive future impact on the meaning of sustainable investment, and thus a part of the debate beyond merely nuclear and fossil gas.