A city is not a city without a subway system – this is not only a common slogan in China, but also an irresistible urge of all Chinese cities.

A subway station in Beijing. [File photo]

After the first subway line opened in Beijing, China has built subway systems in many of its big cities, including Shanghai and Guangzhou, over the past decades. But the real progress was made in smaller cities. According to the National Development and Reform Commission, China's economic planning body, 33 cities applied for subway construction last year and 28 were approved.

These cities differ greatly in geographic location and economic condition. But one thing they have in common is that they can't wait to have their own subway lines. The construction craze across China has provoked a heated debate. Many people wonder whether a subway line is necessary and whether local governments are competent enough to carry out the construction and deal with subsequent problems.

According to Yu Hongsheng, a senior researcher of the Shanghai Academy of Social Sciences, building a subway system is a double-blade sword. On the one hand, it can bridge the gap between the city center and surrounding villages and boost the economy of a large area. On the other hand, it can result in many social problems, such as demolition disputes and work accidents, and pose a great challenge to local governments' capacity to handle crises.