Since the 18th century Asia has been divided into several subregions independently defined from Asia as a whole. There has been no historical consensus and there is not now any universal consensus on the use of these terms, just as there is none for the word "Asia." The areas defined by the United Nations Statistics Division are useful approximations made more fixed by arbitrary assessments of political circumstances, but they are not and cannot be presented as any sort of authority, past or present, on the exact meaning of either Asia or any of its subregions. The major subregions are as follows.
Subregions of Asia in traditional and UN Geoscheme views as below:
3-General data for countries defined as Asian by the UN Statics Division
The United Nations Statistics Division, charged with collecting statistical data on global regions including Asia, publishes a classification standard, United Nations M49, which assigns code numbers to continental regions, areas and countries. Some general data on the countries listed in M49 for the continental region, Asia (142), and one non-official region, "Northern Asia," are presented below. M49 is a device for collecting useful statistics and is a suggested reference guide offered as a global standard for all agencies and institutions that might be interested. The United Nations does not present it as an authoritative standard or as one that is more valid or more worthy of adoption than some other. It is not a requirement for other agencies within the United Nations, which use their own standards as are convenient for their operations. No nations have adopted M49 as a mandatory standard. It does, however, reflect general usage concerning the political geography of Asia. M49 is updated frequently to reflect changing geopolitical circumstances. One problematic aspect of the classification of Asia not yet definitively addressed by the Statistics Division is "Northern Asia," which has no regional code and is not currently officially a region of Asia. Russia, or "the Russian Federation," is a nation of Europe. The "Northern Asia" name is unofficially recognized; for example, the UN Group of Experts on Geographical Names includes an Eastern Europe, Northern and Central Asia Division. "Northern Asia" comes from traditional usage, which divides Europe from Asia at the Ural Mountains. No one at the UN is suggesting that European Russia be included in Asia or that Asian Russia be included in Europe. Their policy is that a nation shall appear once in one region. They have selected Europe. The problem remains unsolved.
4-Subregions of Asia in traditional and UN Geoschememe views
North Asia may mean a-The Asian part of the Russian Federation (Siberia). Although the Statistical Division informally recognizes the existence of this region, according to its one-nation, one-area rule, all of Russia is classified as belonging to Europe. The opposite view, that all of Russia is Asian (bringing Asia west to the limits of Scandinavia) is but rarely seen, as European Russia is the most densely populated. b-Northern Asia as a region of history includes approximately the same territory, with differences in the southern border varying according to historical circumstance. The Ural River and the Ural Mountains (east side) have been the traditional border. Transcaucasia was in the Russian Empire and was considered historically Asian. As the Urals border is internal to Russia and before its fall to the Soviet Union, and therefore is an internal affair, no national or international agencies presume to make any official definitions of a "North Asia."