It was first proposed in the mid 1850s by doctor Ignaz Semmelweis who believed it would reduce mortality rates. It became a widespread thing around 1900 when everyone started doing it because they realized how important decontamination was.
Some factors that may make it difficult to keep speed during a stairway evacuation are exhaustion or the person's mental state. During a period of evacuation, the stress suffered is going to affect how people are going to respond, and how they are going to react. Also, the architecture of the stairway may affect the stairway evacuation process.
The American people had growing distrust of government
<em>The simple answer is:</em>
<h2>It's still an important symbol of Chinese culture.</h2>
