During China’s decades-long housing boom, demand for apartments was so high that cities restricted who could buy homes and limited how many they could buy.

Now, the country’s largest cities are rolling back those rules as they face a different challenge: stubbornly low home prices.

Guangzhou, a southern Chinese city of 19 million people, removed all restrictions on home buyers on Monday. It was the latest in a series of high-stakes economic stimulus efforts policymakers have announced in the past week.

The changes in Guangzhou are in line with other strategies that two dozen smaller Chinese cities have used in recent months. Officials are trying to reverse a grinding property downturn and broader slowdown in growth that has afflicted every corner of the Chinese economy, from the young graduates looking for jobs to the old being able to retire.

Two other major cities, Shenzhen and Shanghai, also relaxed their rules on Monday, without doing away with all home-buying limits. The news that one of China’s biggest cities was trying something bold was an adrenaline shot for China’s stock market, another casualty of China’s economic woes.

An index of big Chinese companies traded in Shanghai or Shenzhen, the CSI 300, rose 8.5 percent after jumping nearly 16 percent last week. And the main gauge for Chinese property stocks in Hong Kong jumped by nearly 10 percent on Monday alone.