<p>Land management institutions are essential for attaining sustainable urban growth. As China's reforms to streamline administration and delegate authority continue to advance, it remains an open question whether transitioning from a highly centralized land management system to a more flexible and decentralized model can yield positive environmental outcomes, warranting rigorous empirical investigation. We examine land approval reform (LAR) as a representative instance of land management reform and assess its effect on urban air pollution (UAP) using a multi-period difference-in-differences (DID) approach. The findings suggest that LAR significantly reduces UAP, with the effect operating through structural, scale, and technological effects. The effects of LAR vary significantly across urban scales, resource endowment types, fiscal pressures, and degrees of land market intervention. Finally, from the perspective of firm behavior, LAR increases corporate environmental investment and enhances green innovation capabilities, thereby effectively constraining pollution emissions. These findings validate LAR's beneficial impact on environmental governance and offer policy-relevant insights for improving land resource allocation and mitigating UAP.</p>