Several South 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, Kolkata (known as Calcutta in 1900) and Dhaka 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. Dhaka grew as a national and financial capital in the later 20th century. In the case of Kolkata nearby cities also grew and became part of the metropolitan area. (West Bengal is mapped for other periods--just not this one. Bangladesh is not mapped for any period.)
The other cities, the ones that ended between 4.0 and 9.999 million metropolitan residents, are: Chennai (in Tamil Nādu and known as Madras in 1900), Bengaluru (in Karnātaka and known as Bangalore in 1900) and Chāṭṭagam (in Bangladesh and known as Chittagong in 1900). (Tamil Nādu and Karnātaka are mapped for other periods, just not this one.)