Well, it was hot and dry that day with high winds. Either this neighbor had no permit but has a lot of influence at city hal, or the fire department issued a permit in error.
People in my part of town (all 5 acre lots, or larger — much, much larger) can get a burn permit after their burn area is inspected by the fire marshall. It must be a certain number of feet from any building and in an open area (away from trees and other brush). Ours is a cleared area out back in a field and is ringed with granite cobble stones. The grass around the cobbles is kept mowed very short. We watch the fire with a tank of water on hand to suppress any flame that threatens to jump out of the ring (about 15 ft. in dia.). Some people have burn barrels, instead.
But, this guy decided to burn his FIELD, and it got out of control. Like I said, either he has influence at City Hall, or City Hall made a big mistake. Lots of CYA going on.