The European Union plans to use €672.5 billion of its COVID recovery cash for projects that will help the bloc realise its ambition of becoming climate neutral by 2050.
EU countries are gradually submitting plans to explain to Brussels how they intend to spend their share of the money.
But environmental activists are already sounding the alarm about a threat to the EU's green ambitions: greenwashing.
Greenwashing is the deceptive marketing method that makes people believe the advertised products, services or projects are environmentally friendly, when, in fact, they are not.
The European Commission is currently examining the complex web of investments, projects and initiatives that make up each country's plan for how to spend the money.
The executive has been in touch with national governments over recent months to ensure the bloc's priorities are incorporated into the final plans. If some aspects fail to meet EU standards, Brussels could request further changes before granting the green light.
Meanwhile, the European Parliament is demanding "greater transparency and democratic accountability" over the plans and the inclusion of civil society in the monitoring process.
"[Firstly] any project which does significant harm to the environment is not eligible [for EU funds]," Siegfried Mureșan, a Romanian MEP from the European People's Party (EPP) group, told Euronews.
"Secondly, we have created a precise methodology on climate tracking, which contains over 180 types of investments which are eligible and also how exactly they are accounted for. For example, if a project is totally a green project, it counts 100%.
"Financing a motorway, a highway is eligible, but only if it contains elements which lead to meeting the climate objective.
"For example, to plant forests around the highway.
"Or to build a certain number of charging stations for electric vehicles to encourage electro-mobility which is less polluting."
Spain: Europe's hydrogen hub?
Spain, badly hit by COVID-19, is set to get one of the biggest shares of the EU's recovery fund. The country has requested €69.5 billion in grants to finance a plan structured around four main pillars: green transformation, digital transformation, social and territorial cohesion, and gender equality.
Hydrogen will be one of the key investments. Prime Minister Pedro Sanchez is already touting Spain as Europe's hydrogen hub, arguing the country has the "best conditions" to tap into this kind of energy, which is poised to become the dominant fuel for land transport by 2050.
The Spanish recovery plan outlines €1.5 billion in investments for the green hydrogen sector, as well as several initiatives for boosting the development of batteries for clean, low-carbon mobility.
But experts worry that most of the funds will end up being green-washed by big corporations.
"The plan of Spain includes significant progress in terms of waste, cities, green taxation, deployment of renewables and ecosystems restoration," Miguel Ángel Soto, from Greenpeace Spain, told Euronews.
"There is evidence that there is an intention to move forward on the Green Deal and all the transversal policies for the energetic transition.
"Over the last year, we have seen how the large companies from the automotive, energy, electricity and tourism sectors have positioned themselves. They have deployed their capacity to influence politics and they have also developed projects for all the regions. And we are really scared that the sector of IBEX 35 [major companies of reference on the Spanish stock market] could finally hoard all the aid."
If the green projects laid out in the recovery and resilience plans fall short of expectations, the EU's goal to cut greenhouse gas emissions by at least 55% by 2030 could be seriously jeopardised.
According to Climate Action Tracker -- an independent scientific analysis that tracks government climate action and measures it against the Paris Agreement -- no European country is on track to fulfil the objective of keeping global temperatures below 2°C.