A state judge on Thursday halted plans for two massive and controversial skyscrapers in Hollywood, ruling that the city of Los Angeles failed to adequately assess the $1 billion project’s traffic and neighborhood impacts.

The Millennium Hollywood project calls for 1 million square feet of office, housing, hotel and retail space near the iconic Capitol Records building and the intersection of Hollywood Boulevard and Vine Street. The two towers of 39 and 35 stories respectively would serve as the project’s centerpiece and would be by far the tallest buildings in Hollywood.

After intense debate, the City Council approved the project in 2013, siding with the developer and proponents who say the project will create jobs, bring much-needed housing and serve as an anchor for the revitalization of Hollywood.

But neighborhood groups, including the Beachwood Canyon Neighborhood Association and a coalition called Communities United for Reasonable Development, filed suit to stop the project, citing concerns about traffic, obstructed views and seismic safety. The project sits very close to an earthquake fault.

In his 46-page ruling on Thursday, Los Angeles Superior Court Judge James Chalfant said that the city failed to fully assess the project’s impacts in its environmental impact report and ordered the city to vacate its approval of the project’s environmental review. That means a new environmental review will likely be necessary before project approvals can be granted.

Specifically, Chalfant said the city failed to address California Department of Transportation’s concerns over the project’s proximity to the 101 Freeway, especially the backing up of traffic along off-ramps and onto the freeway itself.

Chalfant also said the city failed to clearly outline the scope of the project beyond the two skyscrapers, meaning the full impacts of the project could not be analyzed appropriately in the environmental review. And he said the city failed to consider the cumulative impact of other major projects in the vicinity, including the equally massive NBC Universal project.

The ruling was welcomed by plaintiffs.

One plaintiff, community leader George Abrahams, said, “Not only are we fighting to protect the environment, but we are demanding integrity in the process. The victory today is an important step in correcting the rampant abuses from L.A. city hall.”

Notably, though, the ruling did not fault the city for its analysis of the project’s seismic risks. Much of the controversy surrounding the project for the past year has been on the proximity of the Hollywood Fault to the project site, with the state last November releasing a map showing the fault zone running directly beneath the project. Developer and city maps show the fault hundreds of feet away. Chalfant said that the geological engineering studies the city has ordered are adequate to address the concerns.

An executive with project developer Millennium Partners welcomed this part of the ruling and said the developer is looking at options for how to address the other concerns Chalfant raised,

“We are gratified by the judge’s ruling on the seismic issues, acknowledging the appropriateness of our studies,” said Phillip Aarons. “We are considering our options for addressing the issues cited by the court and are fully committed to moving forward with our project.”