Still, the pollution of surface water and groundwater that comes with industrial wastewater discharge remains a problem. Air quality remains satisfactory in cities with heavy industries and high traffic concentration (i.e. Minsk, Mogilev, Novopolotsk and Soligorsk), although there are problem areas within these cities. More than half of the major cities monitored in the period 2005-2013 have reduced emissions from stationary sources, while Zhlobin city (Gomel Oblast) and Novopolotsk (Vitebsk Oblast) have remained the major contributors of pollutants from stationary sources.