とう
あかり, とも
None
Fire you use to light up the street needs to go in a lamp. Campfires, matches? No, none of those work. You need bright, safe lamps to keep the street nice at night.
These street lamps were first used in とうきょう. It was the most advanced city after all. And more people were out at night in とうきょう than anywhere else in Japan. So they needed lamps to light things up!