How did the industrial revolution lead to a downward spiral in death rates?

The Industrial Revolution brought a series of changes to the way societies operated. The changes were massive, but they were not always positive. At the beginning of the Industrial Revolution, death rates increased. This was mainly due to the rise of cities and the urban problems that this brought. Housing was crowded, streets were dirty, sewage was suboptimal and food supplies were unreliable and impure. However, this began to improve towards the end of the 19th century with the Progressive movement.