We examine changes in SO₂ and NO₂ over the world's most polluted regions during the first decade of Aura OMI observations. Over the eastern US, both NO₂ and SO₂ levels decreased by 40 % and 80 %, respectively. OMI confirmed large reductions in SO₂ over eastern Europe's largest coal power plants. The North China Plain has the world's most severe SO₂ pollution, but a decreasing trend been observed since 2011, with a 50 % reduction in 2012–2014. India's SO₂ and NO₂ levels are growing at a fast pace.