Throughout the 19th century Auckland's intense urban growth concentrated around the port in a very similar manner to most other mercantile cities. At this time Auckland experienced many of the pollution and overcrowding problems that plagued other 19th century cities, although as primarily a port rather than a manufacturing centre it avoided large-scale industrialisation, and by 1900, Auckland was the largest New Zealand city. The overcrowding of the inner city had by then created a strong demand for the city to expand, which was made possible when trams appeared in New Zealand around this time, supported by ferry services, mostly to what would become North Shore City.