The DUST project will develop and operationalise novel participatory instruments for proactive and strategic citizen engagement in sustainability transitions. It will combine design-led territorial tools with digital tools for citizen deliberation at scale. The project addresses a defining societal and democratic challenge for Europe, which is to hear the voices of least engaged communities, especially in structurally weak regions dependent on energy-intensive industries, which will be most affected by transitions towards a more sustainable future. Building on the concept of ‘active subsidiarity’, the project will employ an innovative mix of research methods, and experimental citizen participation, to understand the determinants of participation in decision-making on sustainability transitions at different levels of government, and to develop effective policy recommendations for inclusive engagement of civil society.