A processing plant designed to suck carbon dioxide out of the air and deposit it underground started running Wednesday, the companies behind the project said.

The plant is considered to be the largest of its kind in the world.

The plant, named Orca, after the Icelandic word "orka" meaning "energy," consists of four units, each made up of two metal boxes, similar in appearance to the containers used for maritime transport.

Constructed by Switzerland's Climeworks and Iceland's Carbfix, the plant will draw 4,000 tons of carbon dioxide when operating at capacity out of the air every year, according to the companies.

According to the U.S. Environmental Protection Agency (EPA), that equates to the emissions from about 870 cars.

To collect the carbon dioxide, the plant uses fans to draw air into a collector, which has a filter inside.

Once the filters are filled with carbon dioxide, the collector is closed and the temperature is raised to release the gas from the material, after which the highly concentrated gas can be collected.

The carbon dioxide is then mixed with the water before being injected at a depth of 1,000 meters (3,280 feet) into the nearby basalt rock, where it is petrified.

Proponents of so-called carbon capture and storage (CCS) believe these technologies can become a major tool in the fight against climate change.

Critics, however, argue that the technology is still prohibitively expensive and might take decades to operate at scale.

Direct air capture is still a fledgling and costly technology, but developers hope to drive down prices by scaling up as more companies and consumers look to reduce their carbon footprint.

It is one of the few technologies extracting carbon dioxide from the atmosphere and is viewed by scientists as vital to limit global warming, blamed for causing more heat waves, wildfires, floods and rising sea levels.

There are currently 15 direct air capture plants operating worldwide, capturing more than 9,000 tons of carbon dioxide per year, according to the IEA.

U.S. oil firm Occidental is currently developing the largest direct-air-capture facility to pull 1 million tons of carbon dioxide per year from the open air near some of its Texas oil fields.

Climeworks, which recently signed a 10-year carbon removal purchase agreement with major insurance firm Swiss Re (SRENH.S), also offers a subscription service, which allows consumers to pay for carbon removal through monthly payments.