Background <p>Although polycystic ovary syndrome (PCOS) incidence is associated with air pollution, the relationship between air pollution, especially fluctuations in global NO₂ concentrations, and the burden of PCOS remains unclear. In this ecological study, we aimed to investigate this relationship using the Global Burden of Disease 2021 dataset.</p> Methods <p>Data on age-standardized incidence rates (ASIR) of PCOS were collected from 171 countries and regions over a 30-year period (1990–2021). Corresponding data on air pollution (NO₂, SO₂, particulate matter [PM], and O₃) and other indicators were also collected. Mixed linear models and geographic detectors were used to assess the relationship between various indicators and PCOS burden. Furthermore, the weighted quantile sum regressions were used to estimate the effect of multiple exposures to NO₂, SO₂, PM, and O₃ on the burden of PCOS. Utilizing restricted cubic spline regression and subgroup analysis to gain deeper insights into the association between NO₂ and PCOS.</p> Results <p>Results from the mixed linear models and geographic detectors showed that NO₂, SO₂, PM, and O₃ were associated with an increased ASIR of PCOS. Meanwhile, the mixed linear models further demonstrated a positive correlation between the incidence of PCOS and the concentration of air pollutants. In further investigating the relationship between NO₂ and PCOS, we found that the associations between the concentration of NO₂ and ASIR were non-linear (P for non-linear &lt; 0.001). Moreover, the association between NO₂ and PCOS was more pronounced in regions with middle to high economic development.</p> Conclusions <p>The continuous presence and fluctuations in the concentrations of multiple air pollutants, particularly NO₂, may be potential contributors to the increasing burden of PCOS. These findings may suggest that improvements in air quality could be associated with a reduced burden of PCOS.</p>