The gashouse district is an area of a city that used to have a lot of gas companies and factories. These companies would make gas to power things like streetlights and houses. But the gas they made wasn't very clean and it made the air really smelly and dirty.
People who lived in the gashouse district would often have to deal with things like bad smells and hard work, because they might work in the factories or have to breathe in the dirty air.
Nowadays, many of these gas companies and factories are gone, but the gashouse district still reminds us of what it used to be like. Some people even like to visit the gashouse district to see what the old factories and buildings looked like, and to learn about the history of the area.