The Yellow Brick Road stops here.
The 10-episode drama, which was said to be a dark and modern reimagining of L. Frank Baum's original Wizard of Oz story, was ordered straight to series in January and included in NBC's Upfront presentation in May. The network had been advertising Emerald City as recently as late July, at Comic-Con (as of press time, there's even still a page for the show on NBC's website!).
According to Deadline, the network is killing the project because NBC and executive producer Josh Friedman (Terminator: The Sarah Connor Chronicles) had different visions about Emerald City's creative direction. It's still possible that Universal will shop the project elsewhere.
Emerald City is the second show this year to earn a straight-to-series order and then get canceled without ever airing. Earlier this summer, Fox axed its Ancient Egypt-set limited series Hieroglyph, which had been slated to debut in 2015.