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<p>The evolving nature of the COVID-19 pandemic necessitates timely estimates of the resultant perturbations to anthropogenic emissions. Here we present a novel framework based on the relationships between observed column abundance and wind speed to rapidly estimate the air-basin-scale NO<span class="inline-formula">_<i>x</i></span> emission rate and apply it at the Po Valley in Italy using OMI and TROPOMI NO<span class="inline-formula">₂</span> tropospheric column observations. The NO<span class="inline-formula">_<i>x</i></span> chemical lifetime is retrieved together with the emission rate and found to be 15–20 h in winter and 5–6 h in summer. A statistical model is trained using the estimated emission rates before the pandemic to predict the trajectory without COVID-19. Compared with this business-as-usual trajectory, the real emission rates show three distinctive drops in March 2020 (<span class="inline-formula">−42 <i>%</i></span>), November 2020 (<span class="inline-formula">−38 <i>%</i></span>), and March 2021 (<span class="inline-formula">−39 <i>%</i></span>) that correspond to tightened COVID-19 control measures. The temporal variation of pandemic-induced NO<span class="inline-formula">_<i>x</i></span> emission changes qualitatively agrees with Google and Apple mobility indicators. The overall net NO<span class="inline-formula">_<i>x</i></span> emission reduction in 2020 due to the COVID-19 pandemic is estimated to be <span class="inline-formula">22 <i>%</i></span>.</p>