<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 air basin-scale NO<sub><em>x</em></sub> emission rate and apply it at the Po Valley in Italy using OMI and TROPOMI NO<sub>2</sub> tropospheric column observations. The NO<sub><em>x</em></sub> 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 2020 emission rates show two distinctive drops in March (−41 %) and November (−35 %) that correspond to tightened COVID-19 control measures. The temporal variation of pandemic-induced NO<sub><em>x</em></sub> emission changes qualitatively agree with Google and Apple mobility indicators. The overall net NO<sub><em>x</em></sub> emission reduction in 2020 due to the COVID-19 pandemic is estimated to be 21 %.</p>