The World Health Organization estimates that 4.6 million people die each year from causes directly attributable to air pollution. Air pollution damages people, environment, animals, and other components of natural life. It has a high risk priority for the world. Recent studies focus on pollution and other risks for humanity. They propose different solutions to prevent air pollution. In this article, a methodology based on process capability indices (PCIs) has been presented in order to control air pollution. Traditional and fuzzy process capability indices (FPCIs) have been used for this aim. Also, FPCIs are evaluated in the six-sigma approach. The membership functions of PCIs are constructed based on the six-sigma approach. SO2, and particulate matter (PM), also known as particle pollution, are measured and analyzed for air quality. The traditional and fuzzy PCIs are compared for these matters and they are analyzed according to the six-sigma approach. The measurement values of SO2 and PM10 have been collected for 1 year in Istanbul, Turkey. The air pollution of Istanbul has been analyzed by the aid of this method.