The purpose of this study is to evaluate DG ECHO’s approach to reducing the environmental footprint of humanitarian aid by assessing how this policy, and the Minimum Environmental Requirements (MER) developed as a result, have been applied across sectors and crisis contexts, how staff and partners have been supported to operationalise them, and what results have been achieved to date. The study covers DG ECHO-funded actions across all humanitarian sectors, disaster preparedness, as well as internal greening, and innovation and capacity-building supported through ERC funding. The methodology was designed in line with Better Regulation requirements and assessed relevance, coherence, effectiveness, efficiency, EU added value and sustainability. Evidence was drawn from a desk review, a portfolio analysis, key informant interviews, two online surveys, three regional case studies, and a validation workshop. The evaluation found that the Greening Policy is highly relevant and has raised environmental ambition, while increasing operational benefits. Implementation remains uneven across countries and crisis types, constrained by limited engagement, uneven leadership support, capacity gaps, short funding cycles and limited monitoring. In response, three strategic recommendations focus on strengthening DG ECHO’s internal enabling environment, scaling practical field support and capacity building, and improving monitoring for accountability and learning.