A sewer explosion caused by a cigarette became a hot topic overseas yesterday.

Oh my gosh, this is common sense, I wonder how many times I've seen videos like this on the internet and there's still no one who doesn't know. Cigarette butts should never be thrown down the drain! There is a risk of explosion if it comes into contact with flammable gas such as methane gas. This is a fact known to all but an idiot. Those who are less successful are really...(-_-#)