The Impact of New Energy Transition Policies on Synergy Between Corporate Pollution Reduction and Carbon Mitigation

Under the constraints of carbon peaking and carbon neutrality targets, corporate emission reduction is shifting from fragmented governance toward integrated governance that aligns pollution control with carbon reduction and long-term sustainable development. New energy transition policies have become a key instrument for restructuring urban energy, environmental, and economic systems, yet it remains unclear how these macro-level policies reshape firms’ marginal abatement cost–benefit structures and under what governance conditions they generate the synergy within corporate pollution reduction, rather than merely shifting burdens. It is valuable to identify whether, how, and under which governance conditions new energy demonstration city policies enhance the synergy between corporate pollution reduction and carbon mitigation. Guided by system synergy theory and a marginal abatement cost perspective, we use panel data on listed firms to construct a synergy index that jointly reflects multiple pollutant emissions and abatement costs, capturing both environmental effectiveness and economic efficiency. A DID model based on the staggered rollout of new energy demonstration cities is then employed to estimate the policy’s impact on the synergy between corporate pollution reduction and carbon mitigation and its contextual conditions. The results show the following: (1) Inclusion in a new energy demonstration city significantly increases the synergy within corporate pollution reduction. (2) Mechanism analysis indicates that higher municipal attention to green and environmental development and higher corporate ESG (environmental, social, and governance) performance strengthen the positive policy influence. (3) Heterogeneous effects are mainly concentrated in non-energy intensive industries, state-owned enterprises, and small firms, which indicates structural divergence in policy incentives across different types of firms. Overall, this study enriches the studies about the synergy between pollution reduction and carbon mitigation to the firm level, embeds a marginal abatement cost perspective into synergy measurement, and provides an evaluative framework that is consistent with how firms balance environmental and financial objectives. The findings contribute to the sustainability literature by informing the design and assessment of energy transition policies and by offering evidence to refine new energy demonstration city programs so that limited governance resources are directed toward more cost-effective joint gains.