Central Asia is a diverse land with many ethnic groups, languages, religions and tribes. This article discusses all of the above, and includes the demographics of the nations of the five former Soviet republics: Kazakhstan, Kyrgyzstan, Turkmenistan, Tajikistan, and Uzbekistan, a group which has a total population of about 61 million. When Afghanistan, which is not always considered part of the region, is included, then Central Asia has a total population of about 90 million as of 2010. It is to be noted that Pakistan has a large population of Central Asian peoples. Although most central Asians have belonged to religions which were introduced into the area within the last 1,500 years, such as Sunni Islam, Shia Islam, Ismaili Islam, Tengriism, and Syriac Christianity, Buddhism was introduced to Central Asia over 2,200 years ago, and Zoroastrianism, over 2,500 years ago.
Central Asia is the core region of the Asian continent and stretches from the Caspian Sea in the west to China in the east and from Afghanistan in the south to Russia in the north. It is also sometimes referred to as Middle Asia, and, colloquially, "the 'stans" (as the six countries generally considered to be within the region all have names ending with the Persian suffix "-stan", meaning "land of") and is within the scope of the wider Eurasian continent.
In modern contexts, all definitions of Central Asia include these five republics of the former Soviet Union: Kazakhstan (pop. 17 million), Kyrgyzstan (5.7 million), Tajikistan (8.0 million), Turkmenistan (5.2 million), and Uzbekistan (30 million), for a total population of about 66 million as of 2013–2014. Afghanistan (pop. 31.1 million) is also sometimes included.
Various definitions of Central Asia's exact composition exist, and not one definition is universally accepted. Despite this uncertainty in defining borders, the region does have some important overall characteristics. For one, Central Asia has historically been closely tied to its nomadic peoples and the Silk Road. As a result, it has acted as a crossroads for the movement of people, goods, and ideas between Europe, Western Asia, South Asia, and East Asia.
In terms of Asian people, there is an abundance of ethnic groups in Asia, with adaptations to the climate zones of the continent, which include Arctic, subarctic, temperate, subtropical or tropical, as well as extensive desert regions in Central and Western Asia. The ethnic groups have adapted to mountains, deserts, grasslands, and forests, while on the coasts of Asia, resident ethnic groups have adopted various methods of harvest and transport. The types of diversity in Asia are cultural, religious, economic and historical.
Some groups are primarily hunter-gatherers, some practice transhumance (nomadic lifestyle), others have been agrarian for millennia and others becoming industrial or urban. Some groups or countries in Asia are completely urban (e.g., Hong Kong and Singapore); the largest countries in Asia with regard to population are the People's Republic of China, India, Indonesia, Pakistan, Bangladesh, Japan, Philippines, Vietnam, Iran, Thailand, Burma, and South Korea. Colonisation of Asian ethnic groups and states by European peoples beginning in the 16th century, reaching its peak in the late 19th and early 20th centuries (except in the former Soviet Union, which was dissolved in 1990).