HANGZHOU, Sept. 4 (Xinhua) -- The world economy is recovering but faces multiple risks and challenges such as insufficient growth momentum, lack of demand, repeated volatility in financial markets, and sluggish international trade and investment, Chinese President Xi Jinping said here on Sunday.

Eight years after the global financial crisis, the world economy is once again at a critical juncture, Xi said at a summit of the Group of 20 (G20) major economies, which opened Sunday in the eastern Chinese city of Hangzhou.

The growth momentum brought by the previous wave of technological progress is waning while the latest wave of technological and industrial revolution is yet to gather steam, Xi said.

Population ageing and slowing population growth also weigh on the economy and society of major economies, he said.

In addition, economic globalization faces setbacks as protectionism rears its head and multilateral trade arrangements are being impacted.

Despite substantial progress in financial regulatory reform, risks such as high leverage and froth are accumulating, Xi said.