While America is more diverse than it has ever been, some cities remain deeply segregated despite policies enacted to increase integration some 50 years ago, writes Aaron Williams and Armand Emamdjomeh for The Washington Post.

The Post analyzed data from the last 30 years to create detailed maps of the U.S. according to race and diversity.

The analysis showed that, over the last three decades, suburbs have increasingly become the nation’s most racial and ethnically diverse areas.

Michael Bader, an assistant professor of sociology at American University, believes newly built housing is one of the reasons for growing suburban diversity.

“A lot of those areas were developed after the Fair Housing Act was implemented,” said Bader.

Also, lower rental and purchase prices in the suburbs offer more opportunities for population diversity.

According to the map, as of 2016, White Americans are the estimated largest racial group in the Philadelphia-Camden-Wilmington area, accounting for 63 percent of the population. Non-white racial and ethnic groups account for an estimated 37 percent of the population, up from 24 percent in 1990.

But Philadelphia’s suburbs still show clear lines of division, except in larger towns where integration is higher.

Read more about suburban integration in The Washington Post by clicking here.