Spatial Agglomeration of Industrial Nitrous Oxide Emissions Dictates Targeted Mitigation for China's Climate Goals

Nitrous oxide (N2O) currently lacks high-resolution urban data, hindering targeted regional mitigation. To address this, we developed a bottom-up N2O emission inventory for 339 Chinese cities from 2010 to 2024. We find national emissions substantially exceed international estimates due to uncounted industrial sources, revealing a spatial shift from diffuse agriculture to concentrated industrial hotspots, with just 7% of cities generating 40% of the national total. In these hubs, rapid industrial process growth completely offsets energy-efficiency gains, underscoring the urgent necessity for process-specific abatement technologies over general energy policies. Scenario modeling demonstrates that implementing targeted controls in the top-five emitting cities across the six clusters reduces the peak by 9.26%, directly fulfilling the N2O reduction targets under China's 2035 Nationally Determined Contribution. This framework translates macro-level climate goals into actionable municipal roadmaps, providing a critical N2O mitigation reference for cities across the Global South.