We use "on" and "off" to describe the state of devices that have switches like stoves, light bulbs, and automobiles. For fires or flames, we use expressions like "burning", "on fire", "in flames", "aflame", "flaming". When the fire is not burning, we say it is "out". To make it stop burning, we "put it out", "quench it", "smother it", or "blow it out".
In the U.S., I don't hear the word "alight" often, but anybody would know what it means.
These two categories, devices and fires, are handled in distinct ways, even in the same sentence:
Jack: "Is the oven on?"
Jill: "Let me take a look. Yes, I know it is on because I see the flame burning."