Practice of the cross-scale and high-precision eco-environment zoning regulation – “Three lines and one permit”

China's environmental impact assessment (EIA) has played a role in the prevention of pollutant discharge in the two decades of practice. However, the demand for eco-environmental management and the public's environmental aspirations are increasing. The Chinese government is attempting to shift its stance on eco-environment zoning regulation by applying spatial regulatory zoning. Therefore, “Three Lines and One Permit”(TLOP) has emerged as a novel regulatory policy tool developed from ongoing exploration. This paper focuses on the practice of TLOP including delineation at the national level and application at different hierarchy. The results demonstrated that 39,926 integrated environmental units (IEU) in TLOP have been designated nationwide with dynamic updating. Among them, priority protection units, critical control units and ordinary control units account for 54%, 15% and 31% of the country's mainland, respectively. IEU has higher resolution than any previous partition and can better implement the major functional zone strategy. From a regional perspective, the IEUs in the developed eastern region are more sophisticated. The next step for TLOP is to improve the accuracy of IEU in central and western region to meet biodiversity conservation goals, integrate more management targets including synergistic control of pollutants and carbon, enhance the role of information platform services in law enforcement and supervision, and promote TLOP-based researches. Finally, the practice of TLOP provides experience for developing countries. •The “one map” of the country's integrated environmental units was sort out systematically.•The integrated environmental unit is more sophisticated than other regulatory zones.•The resolution of integrated environmental unit in eastern coastal region is higher than in central and western regions.•The multi-scale and refinement of integrated environmental units precisely implement the main function zoning strategy.