Complex sentence: Conditions for the new working-class were often squalid, with much of the population packed into overcrowded and unsanitary tenements, and the city suffered from repeated cholera outbreaks in the mid 19th century.
Split into simpler sentences: Conditions for the new working class were often squalid, with much of the population packed into overcrowded and unsanitary tenements. The city suffered from repeated cholera outbreaks in the mid- 19th century.