San Diego April 18, 2018 7:18 pm San Diego Is Among America's Most Polluted Cities San Diego is ranked the sixth worst smoggiest city in the nation. NBC 7’s Catherine Garcia has the story. US & World Videos 2:25 Spring Valley residents speak out against proposed shelter site 0:20 Suspect shot by deputy along SR-76 in Bonsall 2:21 Warning for Americans traveling to Baja California 10:09 Bodies found in Mexico near where surfers, 2 from San Diego, disappeared | San Diego News Daily 0:23 Pro-Palestinian encampment on UC San Diego campus continues for third day