What Drives Plastic Packaging Waste Generation in Europe? An ESG Panel with Clustering and Machine Learning Validation

European packaging policy is built almost entirely around treatment, while the accompanying prevention obligation lacks an equivalent apparatus of measurable objectives. This article addresses this upstream question directly: what determines the quantity of plastic packaging waste that European economies place on the market? Using Eurostat data, we regress per capita plastic packaging waste on the three pillars of the World Bank Sovereign Environmental, Social and Governance framework for 29 countries between 2014 and 2023. Each pillar is examined through three modules. The first is a panel comparison of pooled, between, fixed-effects, random-effects, weighted, and dynamic estimators, with inference reassessed using a wild cluster bootstrap. The second is an unsupervised classification comparing six algorithms across eleven validity indices, with the dependent variable withheld for external validation. The third is a supervised comparison of six learners under leave-one-out cross-validation, used to validate functional form rather than to forecast. Three findings emerge. Energy intensity and carbon intensity per capita are robustly associated with generation and survive correction for multiple testing, yet environmental country types do not significantly explain differences in packaging burden. Social configurations separate generation along a binary post-transition boundary that does not survive controlling for income, and the sign reversal in life expectancy between the cross-sectional and time dimensions is confirmed independently by the learners. Internet penetration is the strongest association in the study, robust to common time effects and to income but extending to every packaging fraction and therefore not specific to delivery formats, while composite institutional quality is insignificant in every linear specification and suggests, under unrestricted functional form, a threshold rather than a gradient, a shape that a parametric test on the same cross-section cannot locate and that is therefore reported as a hypothesis. Prevention policy must therefore engage determinants beyond waste management. Among these determinants, the diffusion of online retail is currently the most informative.