Several Southwest Asian cities that had at least 4.0 million residents were not mapped. All of them started with fewer than 2.0 million residents in 1900. Two of them, İstanbul (a bi-continental city in a mostly Southwest Asian nation) and Tehrān had between 10.0 and 19.999 million metropolitan residents in 2012. In both cases the growth was due in part to national population growth and in part to urbanization. In the case of İstanbul nearby cities also grew and became part of the metropolitan area. Tehrān also grew due to its being a national capital. (Türkiye and Tehrān Province are mapped for other periods--just not this one.)
The other cities, the ones that ended between 4.0 and 9.999 million metropolitan residents, are: Bagdād (Irāq), Riyadh (in its own province within the Najd or Central Region) and Baṣrah (Irāq). (Irāq is mapped for other periods, just not this one. The Najd Region is not mapped for any period.)