Colombia's Constitutional Court has annulled a controversial carbon credit deal affecting six indigenous tribes in the Amazon rainforest, who claimed it was signed without their consent.

The tribes, residing in the secluded Pira Parana region, accused Ruby Canyon Environmental and Colombian intermediary Masbosques of imposing the agreement illegally.

The deal was intended for the preservation of 7,100 square kilometers in exchange for $3.8 million, sold to Colombian firm Latin Checkout and then to US airline Delta.

The court ruled that the tribes' legitimate representatives must meet within six months to authorize any new deal or halt the project.

This marks Colombia’s first significant legal case against carbon credit agreements, amid growing skepticism of their environmental efficacy.