Climate change activists have gone ahead with planned action to target England's busiest motorway despite a police operation to foil their plans.
Sections of the M25 were closed throughout the Monday morning rush hour as part of the protest by Just Stop Oil.
The demonstrations come as the latest COP27 international climate change talks in Egypt get under way.
Several junctions across Surrey, London and Kent have been impacted.
Specially trained police officers have been deployed.
There have been protests at seven separate locations on the M25: J2 (Darenth), J6-7 (Godstone), J8-9 (Reigate), J13-14 (Staines), J21a-22 (St Albans), J25 (Holmesdale tunnel) and J27 (M11).
The junction between 6 and 7 in Surrey has now reopened after a "protester removal team" dealt with an activist who had climbed onto the motorway gantry.
Essex Police said people had been arrested after reports of people climbing up an overhead gantry close to junction 30 of the M25.
In an emotional video posted from one of the gantries, protester Louise said she was there because she felt she did not "have a future and you may hate me for doing this, and you're entitled to hate me, but I wish you would direct all that anger and hatred at our government".
The 24-year-old added: "They are betraying young people like me. I wouldn't have to be there if they did their lawful duty.
"What we're asking for is what all the scientists are asking for, what the United Nations are asking for, the international energy, the IPCC.
"How many more people have to say we don't have a liveable future if you continue licencing oil and gas for you to listen?"
It comes as the Met Police had launched a "significant" operation to identify and arrest the climate change protesters.
Three people were arrested on Sunday accused of planning public disruption.
Assistant Commissioner Matt Twist said the force had had a "strong reason" to suspect the Just Stop Oil group were intending on disrupting motorways.
He added this was reckless and risked "serious harm to the public".
On Sunday, a High Court injunction was granted to prevent Just Stop Oil protesters disrupting the M25.
From the end of September and throughout October, Just Stop Oil staged 32 days of disruption, which the Met said resulted in 677 arrests, leading to 111 people charged.
According to the group, since its campaign began on 1 April, its supporters have been arrested nearly 2,000 times, with five of their supporters currently in prison.
The Met, which is conducting the operation in conjunction with the National Police Coordination Centre (NPoCC), said more than 10,000 officer shifts had been dedicated to policing the protests since the start of October.
"These are officers who would otherwise be dealing with issues that matter to local communities, such as knife crime, safeguarding and responding to burglaries," Mr Twist said.
"We are determined to bring to justice all of those who conspire to cause significant and unreasonable disruption to London, or cause damage to buildings, property or valuables."
Police are calling on the public to assist with preventing public disruption from protesters by reporting it to 999.
The climate change action group has been calling on the government to abandon plans to licence over 100 new oil and gas projects by 2025 and to do more to help people with skyrocketing energy bills.
In an update on its website, the group said: "This is not a one-day event, expect us every day and anywhere.
"This is an act of resistance against a criminal government and their genocidal death project.
"Our supporters will be returning - today, tomorrow and the next day - and the next day after that - and every day until our demand is met: no new oil and gas in the UK."