Why does China have a single timezone?
Mao Zedong and the Chinese Communist Party moved to a single, nation-wide timezone in 1949.  The government wanted to unify the country, which had previously been divided into five different time zones, and establish a standard time that could be used throughout the country.

The adoption of a single time zone made it easier to coordinate transportation, communication, and other activities across the country. It also helped to promote national unity and identity by emphasizing a shared time system.

However, this decision has led to some practical difficulties, especially for those living in western regions of China. For example, in some parts of western China, the sun may rise and set two hours later than in Beijing, the capital city located in the east. This can make it challenging for people to adjust to a schedule that follows the standard time, which can have implications for their work and daily routines.

Despite these challenges, the Chinese government has maintained its decision to use a single time zone for the entire country.
How much area do time zones typically cover and how is this different from China's singular time zone? Does this cause any problems in particular?