Stock indexes around the globe slumped on worries that growth in China and other emerging markets will be weaker than expected. China is a key commodity consumer, and a slowdown in its industrial purchasing stands to keep the world awash in crude oil and other raw materials for months, and perhaps longer.

Wednesday’s 6.7% drop underscores the central role of oil prices in the world economy. While the oil-price plunge, now in its 19th month, largely has been driven by oversupply during a production boom in the U.S., weaker global demand could delay a price recovery to 2017 or beyond, analysts say.

Some economists also warn that the positive effects of cheap oil on consumer spending could be outweighed by global factors that many analysts underestimated when crude prices began their plunge: job losses, cutbacks in capital spending and declines in government revenues.

Recent fears about global growth underscore the perceived limits of central banks’ power to stimulate national economies eight years after the last financial crisis.

In the U.S., where the Federal Reserve raised interest rates in December for the first time in nine years as part of a process to wean the economy off stimulus, economic data released Wednesday showed a slight decrease in the consumer-price index and an unexpected drop in housing starts in December.

In China, where the government is seeking new ways to stimulate the economy after a debt-fueled investment-spending spree, data this week showed the economy grew in 2015 at the slowest pace in 25 years.

Emerging markets, including China, are seen as crucial to oil-demand growth in coming decades. In developed nations, many economists say, oil consumption is near or past its peak as consumers and companies have become more fuel-efficient.