Only a part of the pollution problem can be visualized here, as data is incomplete. For example, air pollution is reasonably well measured in the US and Europe. But in the developing world, only a few countries, and sometimes only a few cities measure their air quality adequately. You may think, as a result, that the US and Europe look more polluted, as they have many monitors. But this is not the case! In fact, countries with more monitors will probably have more programs to reduce pollution. Many countries do not have any monitors at all and could easily be highly polluted.

Similarly, contaminated site data (usually soil and heavy metals pollution) is available for only some low and middle-income countries. (Please also note that we have not listed any contaminated sites in the developed world intentionally). If you see few or zero contaminated sites in one country or city, this does not mean the place is free of them. Instead, it merely means that there has not been enough study done to find them.

In an effort to fill in the many gaps in the available data, citizens can add their own data, utilizing the ReportPollution.org website where citizen reports are uploaded and then reviewed by Pure Earth for potential investigation as part of its Toxic Sites Investigation Program. These nominations of pollution will be integrated, after validation, and scientific verification, into the Contaminated Sites feature of this site.