Climate activists from The Last Generation group glued themselves to roads and disrupted rush hour traffic in Vienna, Austria on Monday.
Traffic jams were being reported from around 7:45 a.m. local time, according to the police.
The action had been advertised throughout the week, with demands on the Austrian government to set stricter climate goals and reliable measures of climate change.
Among the demands, activists have asked for a speed limit on highways in Austria of 100 km/h and to exit fossil energies.
One street blockade was stopped by police in the morning, the others lasted around one hour.
"We don`t know what else to do, we are desperate," said one activist. "There have been protests for years, but nothing has changed. This is not a popularity contest. We are fully aware that most people do not like us, but it is about the necessary signal effect we are racing into a huge climate catastrophe and it is now important that we wake up, that we get out of the repression."
Another campaigner said, "We put ourselves in the way of the fossil insanity, the government does nothing to meet the climate goals, it does nothing to avoid the global climate collapse."