6. Mumbai, India
When people talk about rapidly-growing populations and economies, China is the country that usually comes to mind, given its current status as the worlds second largest economy (third if the European Union is counted as a single entity) and most populated nation (estimated at 1.35 billion in 2013). India is not far behind, however, with a population of 1.2 billion people and 2014 GDP growth rate of 5.7% that is projected to continue. Though New Delhi is the nations official capital and political centre, Mumbai, formerly known as Bombay, is Indias financial, commercial and entertainment capital, and is a rapidly expanding city as a result of business growth. The growth of illegal enterprise goes in tandem with such growth, however, and Mumbais near 20 million population includes a number of underworld networks that could be incorporated into a GTA game, including the D-Company organised crime syndicate led by kingpin Dewood Ibrahim. Groups such as his have become heavily involved in property as opposed to traditional organised crime activities that have been subject to heavy crackdowns by Indias notoriously brutal police force, but these could both play a part in a rags-to-riches story that could showcase the transformation of a slum-dweller into a criminal equivalent of a maharaja.