Net-Zero Litigation: Procedural Law Aspects

The global rise of the "net-zero" target has ushered in a new phase of climate litigation, where greenwashing and climate-washing are increasingly framed not merely as ethical or communicative issues, but as matters of legal inquiry. Starting from a landmark Italian case (AGCM v. Eni Diesel+), this paper explores the procedural evolution of how misleading commercial practices in the climate context are qualified and adjudicated. It reconstructs the stages of the Eni Diesel+ Italian administrative proceedings up to the 2024 Council of State decision, highlighting the interpretative divergence between the Antitrust Authority, the Lazio Regional Administrative Court (TAR), and the highest administrative court, particularly regarding the application of the "average consumer" test. From a comparative perspective, the article analyzes recent European climate-washing litigation across four sectors: the aviation sector, including the KLM and TUI cases, and the coordinated actions of the European Commission against 20 airlines for misleading climate-related advertising; the ESG sector, through the cases against Vanguard and Mercer Superannuation; the energy sector, through the cases against MSC and EnergyAustralia; and in the ambit of products, through the case against Katjes and Clorox Australia. This contribution reflects on the implications of these case-law developments, in particular on (i) the burden of proof now borne by companies, accompanied by an enhanced role for administrative bodies and civil society actors; (ii) the integration of transparency requirements with substantive obligations, although remedies vary widely and at times fail to be effective; and (iii) the need for an evolving procedural interpretation of unfair environmental practices. Finally, the notion of "voluntariness" in corporate codes of ethics is deconstructed through the lens of constitutional theories of transnational power systems, offering a critical reading of the shift from soft law to enforceable obligations in the realm of private climate law.