Coal gas is a type of gas produced from the carbonization of coal, a process that involves heating coal in the absence of air. This gas primarily consists of hydrogen, methane, carbon monoxide, and other hydrocarbons. Historically, it was widely used for lighting, heating, and cooking before the advent of natural gas. The production of coal gas began in the early 19th century and played a significant role in the development of urban infrastructure. It was often distributed through gasworks and used in street lamps and homes. However, with the rise of natural gas and other energy sources, the use of coal gas has significantly declined.