What are the main causes of Pollution?

What are the different kinds of Pollution? What are the worst types of Pollution? How can YOU help reduce Pollution? Have you started your FREE TRIAL of Who Smarted?+ for AD FREE listening, an EXTRA episode every week & bonus content? Sign up right in the Apple app, or directly at WhoSmarted.com and find out why more than 1,000 families are LOVING their subscription! Get official Who Smarted? Merch: tee-shirts, mugs, hoodies and more, at Who Smarted?