The European Union says that the region needs an additional €175-290 billion in private investment a year (pdf) to become a “climate-neutral” economy by 2050. (That’s $199-330 billion.) That may sound like a lot, but it barely puts a dent in the $5-7 trillion that the UN thinks is needed every year to achieve its Sustainable Development Goals by 2030, which target the environment in addition to a host of other issues.

To plug the gap, “sustainable investing” is spreading from a niche area of the financial sector into the mainstream. Investing along environmental, social, and governance (ESG) criteria is one of the fastest-growing strategies in finance. ESG is not quite as intensive as “impact investing” (investments that must produce a specific and measurable environmental or social impact) but it’s more than just negative screening (cutting out tobacco or firearms stocks from portfolios). Within ESG, it’s the “E” that’s gaining the most traction as global protests and severe weather events push climate policy higher in the public’s consciousness.

But the rapid growth of the field—by some measures, assets committed to sustainable investment strategies represents half of all professionally managed assets in Europe—is raising concerns about “greenwashing.” The industry has grown organically, with organizations deciding for themselves what counts as an environmentally sustainable, or “green,” investment.

Now, the EU has sought to settle the matter.

Last week, the European Commission published a classification system, known as a taxonomy, that details what economic activities are green, and therefore what really counts as an environmentally sustainable investment. The 400-page report by the Technical Expert Group on sustainable finance identifies activities with “the potential to contribute substantially to climate change mitigation.”

What counts as sustainable?

According to the taxonomy (pdf), there are three kinds of activities that make a “real contribution” to climate change mitigation and adaption: first, activities that are already low carbon and therefore compatible with plans for a net-zero carbon economy by 2050, zero-emissions transport; second, activities that are clearly contributing to a net-zero carbon economy, such as low-emissions cars; and third, activities that enable the previous two, such as the manufacturing of wind turbines.

Read the rest of the article at Quartz