The Bank of Japan discussed the need for its new climate change program to be flexible because there’s still no broad agreement on what projects will be considered environmentally friendly.

Board members debated the issue at the June meeting, where the BOJ announced it will introduce a new climate-focused lending program, according to the summary of discussions released Monday.

The summary, which doesn’t identify the speakers, shows the BOJ grappling with one of the main challenges facing policymakers as they take on climate change and its impacts on the economy: coming up with clear definitions of what is green.