@CNN: San Francisco, Stockton and Sacramento were the world’s three “most polluted cities” on Friday morning due to the wildfires raging in Northern California, according to a nonprofit that looks at air-quality data https://t.co/REN3BTQtvZ https://t.co/AR4tuBksZk

San Francisco, Stockton and Sacramento were the world's three "most polluted cities" on Friday morning due to the wildfires raging in Northern California, according to a nonprofit that looks at air-quality data https://t.co/REN3BTQtvZ pic.twitter.com/AR4tuBksZk

— CNN (@CNN) November 16, 2018