What is "town gas" as noted in the book, Talking to Strangers: What We Should Know About the People We Don’t Know?

Town gas was the gas used in homes across Britain after the first world war. Made from coal, the gas was comprised of hydrogen, methane, carbon dioxide, nitrogen, and carbon monoxide. According to several graphs presented in the text, the use of town gas was directly linked to Britain's high suicide rates. After the country transitioned to natural gas, the suicide rate dropped.