This week marks the 83rd anniversary of the first major smog incident in Los Angeles, when reports described a “hellish cloud” of pollution descending on the city. There had been complaints about industrial smoke in the area for a decade prior, but it took some time for L.A. authorities to work out why the problem was getting worse.

The big new contributor was one we’re all now well familiar with: automobile exhaust.

In the midst of a heat wave, the 1943 smog suffocation of L.A. seriously reduced visibility and led to burning eyes and throats. In fact, with World War II still raging, there was some initial concern that the city was under a chemical warfare attack.

While conditions have improved since that summer nearly a century ago, the smog problem hasn’t entirely gone away—and there’s a trail of photo evidence showing how it’s affected Angelenos over the years.

Read more: “Los Angeles Should Be Buried”

Lead image: Los Angeles Daily News Negatives, UCLA Library Special Collections.