The following are the factors that led to the extreme expansion of population in Bombay in the mid 19th century:
1. In the year 1819, Bombay grew the capital center of the Bombay Presidency, thus more people began migrating to the city.
2. The growing trade in commodities such as cotton and opium led the communities associated with trade including traders, artisans, bankers, shopkeepers to settle in Bombay.
3. The establishment of the Cotton Mill in Bombay in 1854, attracted workers from outside.
4. The development of Seaports and railways encouraged people to work in these industries and thus encouraged migration.
5. The attack of severe famines in arid zones brought people to Bombay.
