It's just like the apocalypse!
A town that is known by the name of Miyake-jima in Japan is a site of high activity of volcanic eruption and poisonous gases. Hence the government had to pass laws making gas masks mandatory when people are leaving their place.
So if you're in Miyake-jima, it is alright to forget the grocery list, but not your gas mask.
It is dominated by Mount Ōyama, which is an active volcano and has erupted several times in the past few years.
Every time, sulphuric acids levels go up, the sirens go off, and there is an alert everywhere.
The worst of these eruptions happened in 2000, and 17,500 earthquakes accompanied it.
After the situation was under control, the citizens were allowed to move back in town, but strict rules regarding rules for usage of gas masks were stated.
For full 5 years, the town was off-limits. It was just a pile of dead trees and rusted vehicles. It was a barren land and represented a post-apocalyptic world.
The drills to be followed in case of high levels of poisonous gases were taught to all citizens.
In 2005, the citizens were allowed to come back to the town but by then, 20% of the town was uninhabitable.
Now, the government conducts health checks, blood gas levels, and security measures regularly.