LONDON (Reuters) -The amount of "green" bonds sold by governments, banks and companies has slumped by almost a third this year amid the rollback of climate change policies in the United States and Europe, new figures show.

Data published by Fitch Ratings agency showed overall "labelled" bond issuance, which also includes other types of sustainability-focused bonds, was down 25% year-on-year to $440 billion, with Q2 also the weakest quarter since 2019.

Green bonds - where the money raised is earmarked for environmental or climate projects - had a near $100 billion, or 32%, drop in the year, while the overall share of environmental, social and governance-labelled bonds has fallen back to 10.2% of total global bond issuance from 11.7% for 2024.

The drop off comes as the U.S. under President Donald Trump withdraws from a raft of global sustainability initiatives and rolls back environmental standards.

European Union policymakers are also negotiating proposals that would loosen the bloc's corporate sustainability reporting rules for a large majority of businesses.

Fitch said the main factor impacting the market was the uncertainty around capital expenditure, driven by macro challenges and geopolitical instability.

"Ongoing uncertainty over ESG-related regulations - amid implementation delays and rollbacks in the U.S. and EU - may be prompting issuers to wait for regulatory clarity," it added.