And? Air bursts are much more destructive, hence, why those two bombs were air burst and why most would be air burst in a Russian-U.S. nuclear exchange
Are Nagasaki and Hiroshima inhabited? In a full scale nuclear exchange those that didn't perish by the direct effects of the bomb would die from starvation and disease. The worst of the radiation would decay within a few days but since the modern infrastructure that we all rely on would be gone...