The Lowell City Council voted unanimously on Tuesday to adapt a "hybrid" system for electing its city council and school committee.

The new system, which Lowell residents voted in support of earlier this month over a ranked-choice voting option, reduces the number of at-large city councilors from nine to three, and divides the city into eight districts with eight corresponding district councilors. There will be six school committee members — two at-large seats and four district seats.

The new system will go into effect ahead of Lowell's 2021 municipal election.

The change to include the district city councilors over a council made up entirely of at-large councilors comes after a coalition of Asian-American and Latino residents sued the city in 2017. They argued that the at-large councilor structure did not accurately represent Lowell's population, which is almost half non-white. Few non-white people have ever been elected to the city council or school committee.

The district lines will be drawn by an outside expert after the 2020 U.S. Census data are available, the city said in a statement. Two of the eight districts must be majority-minority, according to the settlement reached between the plaintiffs and the city this May. The district lines "must take into consideration traditional boundaries, including neighborhoods ... [and] must be roughly proportional in population size and regularly shaped."

Oren Sellstrom, the litigation director for Lawyers for Civil Rights who represents the Lowell residents who sued the city in 2017, praised the council's vote in a phone interview on Wednesday.

"It's a more fair and equitable voting system that ultimately is going to result in a more rich diversity of the city's elected bodies — diversity that should reflect the rich diversity of the city itself," Sellstrom said. "And that is going to have a tremendous impact on communities of color that will see themselves represented in the elected bodies and ultimately will strengthen the city as a whole."

Lowell City Councilor Vesna Nuon said on Wednesday he thinks that splitting the Council into districts will encourage higher participation in local government and will more accurately reflect the city's diversity.

"You're going to have Hispanic [representation], you're going to have Asian [representation], you're going to have other ethnicities [at] the table. You can have more voice into how we can make the city better," Nuon said. "And that's what we're looking for — more voice involved in the process of how we can move the city forward."

In a statement, Lowell Mayor William Samaras said that the restructuring "will allow our city council and school committee to better serve our community" and that he was "confident that our new election system will be successful in making Lowell’s government more reflective of our diverse community."

WGBH News' Mark Herz contributed to this report.