Four days of hearings in a unique lawsuit over climate change between Dutch-Anglo oil giant Shell and 17,000 Dutch citizens wrapped up on Thursday.

Milieudefensie, the Dutch branch of Friends of the Earth, is leading the case against the Amsterdam-headquartered multinational and demanding the company reduce its carbon emissions by 45% by 2030 to reduce the pace of global warming.

The environmental group argues that Shell is violating Dutch liability law by emitting double the amount of carbon dioxide as the country as a whole. Shell contends those emissions don’t come from its headquarters but its subsidies in some 80 countries around the world, and any complaint must be taken up with them directly.

Milieudefensie director Donald Pols told reporters before hearings started in the first week of December that the lawsuit was ‘unique’. If the environmentalists are successful, it would be the first time a court would order a private company to change its business model to reduce its carbon footprint.

Shell argued that it can’t be held liable in the Netherlands for events that take place worldwide. ‘The scene of the crime, in this case, is the location where the emissions take place,’ a Shell lawyer told the court.

Activists worldwide are watching the case closely. Following a 2019 Dutch Supreme Court ruling, known as the Urgenda decision, the Dutch government was ordered to reduce greenhouse gas emissions by 25% of 1990 levels by the end of 2020. The cabinet announced further measures last week in an effort to meet the target by the end of the year.

That ruling found that the Dutch government was required to meet the conditions of international treaties, including the Paris climate agreement. In the present case, Shell argues that because it isn’t a party to such treaties, as they are between nations, it isn’t obliged to meet their targets.

A ruling in the case is expected in May 2021.