South Korea’s National Pension Service (NPS) is being challenged by climate groups demanding for the retirement fund, one of the world’s largest, to disclose details of discussions over limiting investments in coal.

Three activist groups jointly filed a case on Tuesday at the Seoul Administrative Court accusing the welfare ministry, which oversees the fund, of refusing to release minutes of meetings at which coal divestment policies were discussed, the campaigners said in a statement. NPS declined to comment on the case.

NPS is required by law to share details or documents related to management committee meetings, typically after a year has elapsed. Minutes can be withheld for four years if their publication is judged to have the potential to impact the fund’s performance or market stability.

The fund, which manages assets worth about 976 trillion won (S$1 trillion), had been expected to outline details in 2022 of how it would reduce holdings in companies with ties to coal after pledging in 2021 to adopt investment-restriction strategies. NPS holds stakes in companies with coal-linked investments including Korea Electric Power Corp and Posco Holdings.

Though major global pension funds have pledged to align their portfolios with international climate targets, the task has been complicated by weaker performance of ESG funds and after fossil fuel producers reaped bumper profits from a squeeze on fuel supplies prompted by Russia’s invasion of Ukraine.

President Yoon Suk-yeol’s government has in 2023 also lowered short-term targets for renewable energy additions, and eased the burden of emissions reduction on some major polluters.