Climate activists from Extinction Rebellion on Tuesday disrupted London Concrete, the British capital's biggest supplier of ready-mixed concrete which supplies a major road tunnel project under the River Thames.
Activists blocked entrances to the site. The group said it would disrupt the site for the day in an attempt to halt the expansion of the works.
"Concrete has a huge environmental impact and building another tunnel will only make air pollution across East London worse," said Eleanor McAree, 25, from Extinction Rebellion.
"Air pollution is already at dangerous levels and is affecting the health of children and adults in the area."