Many developing countries have been experiencing the problems of urbanization, particularly regarding carbon emission and polluted air emission mitigation. Is it possible to simultaneously achieve these two different clean and green economic strategies? This study analyzes this paradoxical issue of air pollution in terms of PM_2.5 efficiency. To evaluate the performance of regulatory policies on air pollution and to find out the governance factors, this paper adopts the stepwise approach. In the first stage, we evaluate the cross-sectional PM_2.5 efficiency of 16 Korean municipalities for the period between 2012 and 2017 and determine whether this performance is sustainable using the Malmquist Productivity Index (MPI). We concluded that most local governments lack sustainable governance on regulation policies for clean air. Using the Tobit model in the second stage, this study showed that regional economic development (GRDP) and an patent for clean air technology innovation are the most important strategic factors that promote sustainability in regulation policy performance.