<p> Most of our data are based on perceptions (opinions) from visitors of this website. For pollution section, we include some relevant data from World Health Organization and other institutions if we find it helpful. <p> <I>Pollution Index</I> is an estimation of the overall pollution in the city. The biggest weight is given to air pollution, than to water pollution/accessibility, two main pollution factors. Small weight is given to other pollution types. <p> <I>Pollution Exp Scale</I> is using an exponential scale to show very high numbers for very polluted cities, and very low numbers for unpolluted cities. Therefore to calculate formula it uses the exponential function to calculate the index. <p> Actual formulas to calculate indices are subject to change. At this moment, quite complex empirical formulas are used.
