Austria has filed a legal challenge over the inclusion of nuclear energy and natural gas on the European Union's list of "green" investments.
"What I oppose with all my might is the attempt to greenwash nuclear power and gas via the backdoor of a supplementary delegated act," Leonore Gewessler, Austria's Federal Minister for Climate Protection, Environment and Energy, told reporters.
"I think it is irresponsible and unreasonable. From our point of view, it is also not legal," she added.
Austria had previously stated it would take legal action within hours of the European Parliament backing the EU plan to include nuclear and gas in the upcoming taxonomy back in early July.
The taxonomy is a classification to give the financial sector clarity on which economic activities can be considered sustainable that has been in the works for years.
The European Commission's decision to add nuclear and gas to the list was criticised as highly political and came after heavy pressure from both France and Germany which both heavily rely on nuclear and gas respectively.
Twelve environmental NGOs including Greenpeace, WWF, ClientEarth and Transport & Environment (T&E), launched their own legal challenge against the Delegated Act last month arguing that it violates the taxonomy regulation itself as well as the European Climate Law and the bloc's obligations under the 2015 Paris Agreement.
Austria, which filed its motion at the Court of Justice of the European Union, is hoping that other member states will rally behind its challenge.
Luxembourg, which also criticised the Delegated Act in July, "has already announced that it will join this initiative," Gewessler said.
The minister highlighted that its case rests on "16 sticking points."
Nuclear, she said, is associated with "incalculable risks" including the "unresolved final disposal of radioactive waste" which does not fulfil one of the taxonomy's central criteria that any economic activity deemed to "cause significant harm" cannot be included. She cited Hiroshima, Fukushima and the risks the Russian invasion of Ukraine pose for the war-torn country's nuclear power plants.
She also argued that nuclear is "far too expensive and also far too slow to be able to make a contribution in this critical decade for climate protection."
Natural gas, meanwhile, is a fossil fuel is "cannot be ecological by definition," she said.
"It releases huge amounts of CO2 causing methane emissions all along the extraction and transport chain fossil gas harms our climate and climate harms the natural gas for electricity production."
"It weakens the credibility of the taxonomy as a meaningful tool, as a credible and consistent instrument in finance, and also creates disincentives for investment in our energy system because it delays the urgently needed investments in the energy transition, because cheaper and more quickly available renewable energies are already available," she said.
Finally, for Austria, the Commission overreached by issuing a Delegated Act to add to the taxonomy, after the regulation had been approved by member states.