What is the most populous country in the world?

China is the most populous country in the world and has maintained this status for several decades. As of the latest data, China's population exceeds 1.4 billion people, making it the largest country by population. This significant population is a result of various historical, social, and economic factors, including long-standing agricultural practices and urbanization that have supported large populations over many generations.

Additionally, China has implemented various policies over the years, such as the one-child policy, which was in effect from 1979 to 2015, significantly influencing its demographic trends. Despite recent challenges such as low birth rates and an aging population, China remains the most populous nation.

In contrast, while India also has a rapidly growing population and is expected to surpass China's population in the coming years, as of now, it is not the most populous. The United States and Indonesia, although large in population, do not rival the sheer numbers of China or India.