As we prepare to celebrate the legacy of Martin Luther King Jr., we should be cautious about congratulating ourselves for having overcome segregation and the resultant inequality against which King is best known for fighting. Indeed, the problems of racial segregation in housing and education are no less urgent than they were 40 years ago.

A study published this past May in the American Sociological Review shows that today, blacks and whites overwhelmingly live in neighborhoods with members of their own race. Though they do so by choice, this is still problematic because, as a 2011 study from the Joint Center for Political and Economic Studies found, in the cities with such high levels of racial segregation, blacks and Latinos live far shorter lives than whites and are much more prone to long-term health problems, like asthma, due to higher pollution levels.

The picture is no brighter in public schools, as a report issued in September by the Civil Rights Project at UCLA shows. It found that school segregation for blacks, Latinos and poor students has returned to levels we haven’t seen since the 1970s. And we know from 30 years’ worth of research that test scores and college-level success are far lower for students who attend racially segregated schools. Nonetheless, in our present moment, 60% to 80% of districts in major metropolitan areas like Chicago, New York, Philadelphia, Los Angeles and Dallas have schools that are overwhelmingly segregated by race.

Read more at TIME.