In the last few years, China released national cross-sector action plans to address its air, water, and soil pollution. These action plans establish targets and timelines for pollution reduction, taking aim at high-polluting sectors and articulating strategies for controlling emissions. In this perspective, we demonstrate the need for transparent, accurate methods and data appraising the financial expenditures and investments required to fund these plans. Applying a unique dataset on project-specific abatement costs derived from official but largely non-public Chinese data sources, we calculate the cost of China's pollution clean-up to be $1.1 trillion USD. Given slowing economic growth, we assess a roughly $900 billion USD shortfall based on analysis of existing public environmental expenditure and local government investment, necessitating private sector funds and new finance mechanisms if the plans' benefits are to be fully realized. To spur these new approaches, we argue that additional data disclosure and transparency regarding cost calculations are needed. We identify key questions and next steps for further research and policy discussion on what data are needed to underpin these improved estimates of China's pollution clean-up costs.