The writing process for the majority of Metallicaâs albums have followed the same process. A large slew of guitar riffs written primarily by James Hetfield, sometimes Kirk Hammett, and rarely the bandâs bass player, (that now being bass virtuoso Robert Trujillo) are reviewed and selected.
1 Delhi is most polluted city in the world in PM2.5 concentrations. 2  Half of the top 20 most polluted cities were in India, according to data.  PM2.5 is considered most harmful to health.
Still, in Los Angeles, residents have experienced an average of 117.7 days of high ozone levels each year, the most of any U.S. metropolitan area. 24/7 WALL ST.: The rest of the 10 most polluted U.S. cities. 24/7 Wall St. is a USA TODAY content partner offering financial news and commentary.n the 2015 report, six cities set local records for the most days with dangerously high levels of particle pollution, including the San Francisco and Visalia, Calif., metropolitan areas.