A global environmental activist working on an effort to coordinate a global treaty to phase out fossil fuels was detained and released by Indian authorities as part of their probe into the use of foreign funds to undermine Indian energy policies, Indian officials said on Wednesday.

India’s Enforcement Directorate searched the home of Harjeet Singh and his wife Jyoti Awasthi, who run environmental NGO Satat Sampada (Nature Forever), as part of its investigation into “suspicious foreign inward remittances” received by the organization to promote the so-called Fossil Fuel Non-Proliferation Treaty within India, it said in a statement.

The treaty, first proposed in 2022 by Pacific island nation Vanuatu, seeks to stop the production of fossil fuels and usher in a transition toward green energy. It is backed by 18 developing countries, including Colombia and Pakistan.

The probe comes after the conclusion of COP30 climate summit in Belem, Brazil, where several countries objected to a final outcome that avoided stronger plans for reining in greenhouse gases or phasing out fossil fuels.

“While presented as a climate initiative, its adoption could expose India to legal challenges in international fora like the International Court of Justice and severely compromise the nation’s energy security and economic development,” the Indian agency said in a statement.

The ICJ issued an advisory opinion last July that said wealthy nations have a responsibility to curb climate change.

Singh and Awasthi were not immediately available for comment.

Tzeporah Berman, founder and chair of the Fossil Fuel Non-Proliferation Treaty Initiative, could not comment on details of the probe but said in a statement that the treaty aims to support, not undermine India.

“The proposal intends to support developing countries — including India — through international cooperation, economic diversification, access to finance, and technology transfer. Our purpose is to advance fair and orderly transitions to renewable and accessible energy systems, with a particular focus on those most in need,” she said.