Thousands of environmental activists brought parts of central London, including Oxford Circus, Marble Arch and Waterloo Bridge, to a standstill on Monday.
Extinction Rebellion said their intention was to conduct non-violent acts of resistance and "peaceful action" but three men have been arrested on suspicion of criminal damage near the Shell HQ.
Protesters also gathered at Marble Arch, situated at the end of Oxford Street, at Piccadilly Circus, and Parliament Square.
The blockades continued throughout the day but as darkness fell officers moved in and began to arrest people on Waterloo Bridge in an effort to clear it.
The "Extinction Rebellion" protestors have promised to continue their action throughout the week.
Extinction Rebellion said the protests across London were just some of dozens planned across the world, calling for governments to introduce stricter measures to tackle climate change.
The busy Thames crossing was closed to traffic in both directions this morning, Transport for London (TfL) said. "We wish to make peace with ourselves by making peace with our neighbour Earth and with our God", he said.
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Police have advised Londoners to leave extra time for their journeys because of possible delays caused by the protest.
There were loud cheers, the ringing of bells, and the blowing of whistles as people were quickly arrested and taken to police vans.
Extinction Rebellion, which generated headlines with a semi-nude protest in the House of Commons earlier this month, is demanding the government declare a climate and ecological emergency and reduce greenhouse gas emissions to net zero by 2025.
"This crisis is only going to get worse ..." It could be there are more arrests at night and people are ready and willing.
Police carried some protesters off Waterloo Bridge.
The figure includes three men and two women who were arrested at the United Kingdom offices of energy giant Royal Dutch Shell on suspicion of criminal damage.
But later on Monday the Met issued an order under section 14 of the Public Order Act, which allows conditions to be imposed on public processions and assemblies.