Ecological accountability is a key factor to promote ecological civilization construction in China. As its implementation mechanism, central environmental inspection is regarded as the toughest and unprecedented environmental policy in China（Chen et al., 2019）. Prior studies have found that central environmental inspection plays a positive role in environmental supervision（Li et al., 2020）, as the cross-hierarchy governance of “top-driven” in the design of its implementation mechanism strengthens the rigid binding force of environmental law enforcement. Especially for enterprises which cause serious environmental pollution, central environmental inspection urges them to reduce pollution emissions through improving production processes. Based on the quasi-natural experiment of central environmental inspection, we use the multiphase DID method to examine the effect of ecological accountability on enterprises’ green process innovation, and the moderating effect of media reports.

We use the data from industrial enterprises listed in Shanghai and Shenzhen A-shares from 2012 to 2018, and take heavy-polluting enterprises as the treatment group and non-heavy-polluting enterprises as the control group. The results show that central environmental inspection significantly promotes enterprises to increase their investments in green process innovation, which indicates that ecological accountability has a significantly positive effect on green process innovation. We further demonstrate that the effect of ecological accountability on green process innovation has heterogeneity in different media reporting contexts. Specifically, the positive effect of ecological accountability on green process innovation is significant for enterprises with less media reports or more negative media reports rather than enterprises with more media reports or more positive media reports. Besides, the robustness of the results is verified by parallel trend test, randomness test of policy time and heterogeneity test of media reports.

The contributions are as follows: Firstly, prior studies have investigated the incentive effect of central environmental inspection on green technology innovation（Li et al., 2021）. This paper further enriches the literature through studying the effect of central environmental inspection on green process innovation. Secondly, whereas existing literature mainly discusses the role of central environmental inspection in the political context（Cheng & Hu, 2019; Wang et al., 2021）, it further expands the research on the context of ecological accountability through exploring the moderating role of media reports. The conclusions provide some policy inspirations: It is necessary to strengthen the external supervision role of media reports on the environmental pollution behavior of enterprises, which can make up for the shortcomings of the implementation mechanism in central environmental inspection. In addition, the external supervision that enterprises face should be strengthened to encourage them to develop green process innovation.