A child marches in environmental protest in Richmond, California. (Shadia Fayne Wood)

Richmond, California is home to the Golden State’s single largest greenhouse-gas polluter, the Chevron oil refinery and some of the fiercest local environmental politics and activism anywhere in the country.

On Saturday, police arrested more than 200 people for trespassing at the refinery gates, as more than 2,500 demonstrators gathered there in a protest over climate change and air pollution, according to reports in the San Francisco Chronicle and Bay Area radio station KQED. Protesters marked the one-year anniversary of an August 6, 2012 explosion at the Chevron refinery that sent 15,000 people across the region to hospitals with respiratory problems. The refinery was also one of the key symbolic sites that Bill McKibben’s organization, 350.org, chose for its series of protests this summer—to draw attention to climate change, the fossil-fuel industry’s role in blocking environmental policy, and the plight of people living in the shadow of industrial pollution.

Richmond is one of the country’s best case studies on how oil mixes with politics. The refinery has loomed over Richmond for more than 100 years and has had a heavy hand in local elections and decisionmaking. “They basically ran this place as a company town,” Andres Soto told the San Francisco Chronicle last August. More recently, public sentiment turned against Chevron. Five years ago, Chevron lost sympathetic members of the city council, according to Richmond Confidential, a news site produced by the University of California, Berkeley, journalism program:

Before the progressive victory of 2008, Chevron enjoyed the support of a majority of legislators at Civic Center, the seat of Richmond’s city government. Since then, Chevron has seen Richmond, home to one of its largest refineries in the nation, drift further to the left under a predominantly progressive administration led by mayor Gayle McLaughlin of the Richmond Progressive Alliance [RPA].

In the years since, RPA has strived to hold Chevron accountable on air quality, safety and other issues—such as back taxes owed to the city. On Friday, the city filed a lawsuit against Chevron over last year’s refinery fire: NBC reports the legal complaint accuses the company of “lax oversight and corporate indifference to necessary safety inspection and repairs.” The mayor and local activists have also opposed California’s cap-and-trade regulations (breaking ranks with some environmental groups), arguing for a mandate that would force Chevron to reduce its greenhouse-gas emissions locally.

It will be an ongoing battle for those Richmonders who want the city council to continue a watchdog role against Chevron. In 2012, when two RPA candidates for Richmond city council lost, it was in large part because Chevron pumped $1.2 million into local campaigns.

Saturday’s protest drew national attention to the political and environmental struggles of Richmond, and to the challenge the climate movement faces confronting a high-profit, polluting industry with big profits, big influence and deep pockets for lobbying and campaign contributions.

Former Obama campaign staffers protest the Keystone pipeline.