Abstract:This study investigates what conditions, in combination, drive varying levels of intensity of inter-organizational activities regarding cooperation on environmental governance in nine urban agglomerations in China. This article distinguishes strong and weak inter-organizational activities; and through a literature review, the article distills five conditions influencing inter-organizational activity, including vertical meta-governance, horizontal meta-governance, leadership, autonomous capacity disparity and environmental status disparity. While these conditions are clearly unique, it is unclear if any of these conditions are necessary or sufficient and how they work collectively, for varying degrees of inter-organization activities. Through the method of Qualitative Comparative Analysis (QCA), the article examines this question. The findings suggest that strong horizontal meta-governance and strong leadership are both necessary conditions for strong inter-organizational involvement in joint environmental governance. Small disparities in autonomous capacity and environmental status are sufficient conditions for strong inter-organizational activities. Strong vertical meta-governance is neither a necessary nor a sufficient condition. The QCA results reveal that local authorities should put energy in developing their formal structures favorable for cooperation and that local leaders should develop skills to facilitate joint actions between member cities in an agglomeration.