Mumbai

Bombay duck is a fish, dried and pungent, with no bird in it at all.

The fish, bombil to Marathi speakers, was landed and cured around Bombay, now Mumbai, and the dried slabs traveled inland by rail. The duck half is unexplained; a popular guess ties it to the mail trains, the Bombay dak, but nothing supports it.

Bombay became Mumbai in 1995; the sandwich kept the old name anyway.

Cart vendors in the city have sold the stacked, chutney-smeared version since the mid-20th century, and menus across India and abroad still print it as Bombay. Food names travel more slowly than maps do, so the sandwich preserves a city name the city itself retired.