The impact of new energy demonstration city policy on the mental health of middle-aged and older adults

China’s initiative to develop new energy demonstration cities aims to drive economic restructuring and green development by targeting urban energy use, air quality, and industrial impacts, yet its effects on middle-aged and older adults’ mental health remain underexplored. This study investigates these effects using data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2020, focusing on 8988 participants and employing a difference-in-differences model to evaluate self-reported health and depressive symptoms. First, the research finds that new energy city projects significantly improve mental health in middle-aged and older adults, with participants exhibiting fewer depressive symptoms, the results validated through multiple robustness checks. Second, these mental health benefits are mediated by improved energy efficiency, better air quality, increased employment opportunities, energy transitions, enhanced social activities, and higher life satisfaction. Third, the magnitude of these benefits varies across demographics, with greater improvements observed among middle-aged and older adults with higher cognitive abilities, urban residents, and those in eastern China.