Nippon Life Insurance Co. will no longer extend loans for, or invest in, coal-fired power plants due to environmental concerns, an official at Japan's biggest life insurer said, in the first such move by a major domestic institutional investor.

Japanese banks in recent months have tightened lending criteria for coal power, indicating a global divestment of fossil fuel assets that has cut $6 trillion worth of investment has reached the world's third-biggest economy.

"We have decided to stop new investment and lending to coal-fired power projects at home and overseas," Yusuke Takaishi, deputy general manager at Nippon Life's finance and investment planning department, said in an interview.