In a sweeping new study of more than 13,000 urban areas worldwide, researchers have mapped air pollution levels and carbon ...

from climate change to deforestation to plastic pollution. We're taking a look at what you need to know about this year's Earth Day events, as well as looking at some fascinating Earth Day facts.

In a sweeping new study of more than 13,000 urban areas worldwide, researchers have mapped air pollution levels and carbon dioxide emissions, providing comprehensive global analysis of urban ...