In the late 19th century poor hygiene greater access to mass public transportation and growing city populations all contributed to?

In the late 19th century, poor hygiene, increased access to mass public transportation, and growing city populations contributed to the spread of Infectious Diseases. Urban areas became overcrowded, and inadequate sanitation infrastructure exacerbated health risks, leading to outbreaks of illnesses like cholera and tuberculosis. Public health reforms and awareness began to emerge in response to these challenges, ultimately shaping modern sanitation practices and urban planning.