Nearly 1 child in 7 worldwide — or 300 million kids — lives in an area that has high levels of outdoor air pollution, a UNICEF report released Monday says. Most of the affected children — 220 million — live in South Asia. Sources of pollution include factories, power plants, burning waste, dust, and vehicles that use fossil fuels, which "don't only harm children's developing lungs, they can actually cross the blood-brain barrier and permanently damage their developing brains," UNICEF executive director Anthony Lake said in a statement.