Pipelines of all types are fragile things and break all the time for numerous reasons.
Do not attribute to malice which can be explained by negligence/incompetence with out evidence.
The Nordstream pipelines were not in operation, which indicated the need for maintenance. The pipelines, which carry methane under saltwater, require frequent preventive maintenance checks and services, however, it is believed that these checks may have been neglected since the Russians took over. The pipelines were officially shut down for maintenance in July 2020 and July 2021, but were met with various issues and disruptions in gas flow.
Given the pressurized and highly flammable nature of the pipelines, it is imperative to determine the causes of these issues.
Sabotage cannot be ruled out, especially given the current geopolitical climate.
However, the most likely cause could be related to the formation of methane hydrates, which can cause blockages in the pipeline known as hydrate plugs. These plugs can be difficult to remove and require a slow and simultaneous depressurization from both ends of the pipeline.
Remember, both sides, this is important!
If the depressurization is not carried out correctly, it can result in the rapid launch of the hydrate plug towards the depressurized side, causing significant damage to the pipeline. The Diesel Effect, which occurs when the valves are closed ahead of the fast-moving plug, can also cause significant damage. It is crucial that the removal of hydrate plugs be carried out by experienced professionals, given the potential consequences of a failure to do so.
https://www.stssensors.com/blog/2020/07/01/the-diesel-effect...
EDIT: Formatting