Was it a result of domestic political changes or of developments in international environmental politics? While the decision to introduce comprehensive modern environmental policies in China has had arguably a long-term impact on environmental governance, few studies have scrutinised the early decision-making process. This article attempts to address the void in scholarship. Adopting the multiple streams framework, the authors argue that the origins of environmental policy in China arose from the confluence of three streams—problem identification, political tensions and policy choices—under Premier Zhou Enlai's sponsorship. The new ecological perspective arising from the environmental policy emphasises scientific principles and technocratic solutions, lending a contrast to an ideological approach that had characterised the previous decades. This process was accompanied by the new political role of an environmentalist group consisting primarily of bureaucrats and scientists who mobilised international experience to identify appropriate technological solutions. This article analytically traces the historical context, problem identification, policy entrepreneurship and key policy instruments that characterised the first phase of Chinese environmental policies. The authors discuss the extent to which key elements of China's environmental policies today may still be shaped by the technocratic approach in the initial phase.