China's pledge to stop building coal-fired power plants overseas could cull $50 billion of investment as it slashes future carbon emissions, analysts said, although Beijing's own domestic coal program is still propping up the dirty fossil fuel.

Chinese President Xi Jinping said in a prerecorded address at the United Nations General Assembly on Tuesday that China would help developing countries build green energy production facilities and halt the construction of coal power plants abroad.

China has been under international pressure to announce an end to overseas coal financing as part of its updated package of national climate pledges to be submitted to the United Nations.