To obtain relevant literature to underpin the arguments in this paper, a comprehensive literature search spanning both policy-related documents (e.g., regulations, guidelines, analysis, dossiers) and scientific literature was conducted using keywords like "persistent, mobile and toxic", "very persistent very mobile", "substance grouping" and "chemical regulation" in electronic databases such as PubMed and Google Scholar, while filtering for relevance. As the study focus area was mainly the European Union, recent policy documents in the EU and United Nations were considered most relevant due to the greater activity on PMT/vPvM substances, while detailed policy analysis of areas outside the European Union was considered out of scope. Scientific studies focused on grouping strategies for the assessment and management of substances, including chemicals, pollutants, and contaminants that exhibit persistence and mobility in the environment were also considered relevant. Backward citation searching was also conducted from the list of relevant articles to identify additional studies that may have been overlooked during the electronic search. By systematically executing the search strategy across multiple databases and supplementing it with hand-searching reference lists, a comprehensive selection of relevant literature with findings focused on the topic was compiled and considered in this article.