What is the time zone, 24 types of time zones and how they are calculated?

A time zone is a geographic region in which all the clocks have the same time. This is done to ensure coordination and simplify communication between people in different locations. The world is divided into 24 time zones, each approximately 15° of longitude wide, which are offset from Coordinated Universal Time (UTC) by whole hours. For example, Eastern Standard Time (EST) in North America is 5 hours behind UTC, while Pacific Standard Time (PST) is 8 hours behind UTC.