What is urban fantasy?
A fantasy story set in a city.
A simple definition. With that, you could have a story of jinni and magi in late 19th century Istanbul, an occult detective solving supernatural crimes in 1920s New York, a half-elf mercenary working a corporate contract against a clan of dragons in the Hong Kong of 2121, and they would all fall under the rubric of urban fantasy. What they all have in common is that the interpretation of fantasy through the eyes of a modern-day city-dweller. A fantasy in which an urban lifestyle plays a significant role. It is a modern genre, a modern fantasy.
And in many cases, too modern.