Protesters wearing gas masks and high-visability clothing blocked Cranbourn Street outside Leicester Square tube station in London, and Great Ancoats Street in Manchester in a demonstration called “The Air We Grieve”.
In London, activists used 25 cement blocks to represent the number of people who die each day as a result of air pollution, with six protesters glueing their hands to the yellow breeze-blocks.
And in Manchester, protesters held a banner saying: “Air pollution kills 1,200 Mancunians a year.”
Writing on Twitter, Extinction Rebellion Manchester said: “Sorry for the inconvenience this morning folks, today we are highlighting @ManCityCouncil inaction over the illegal pollution levels in Manchester.
“It’s three days till the election, lets make this the #ClimateElection #ActNow #XR #ExtinctionRebellion.”
Extinction Rebellion London tweeted: “Air Pollution is already killing 25 people a day in London and affecting millions more around the world.”
Police later arrived in the street, which protesters said has “dangerously high levels of air pollution”.
A Metropolitan Police spokesperson said: “Police are aware of a small number of protesters outside Leicester Square Underground station. Officers are in attendance.”
One protester, a teacher called Rosamund Frost, said: “We are here demanding action on illegal levels of toxic air in our communities, our schools and our streets.
“In February 2017, the European Commission issued a ‘final warning’ to the UK over illegal levels of air pollution.
“In May that year, after the government failed to take decisive action, they were taken to Europe’s highest court, the European Court of Justice.
“The government have neglected to tackle fatal levels of air pollution. How can we put our trust in them to address the broader climate and ecological emergency?”
Meanwhile, other Extinction Rebellion protesters entered their fourth week on a hunger strike outside political party headquarters in Westminster.
The strikers, including 76-year-old grandfather Peter Cole, have sent a letter to Boris Johnson, inviting him to discuss the climate and ecological emergency with them on Monday.
Additional reporting by agencies