Neutron bomb - Wikipedia
Causes deadly neutron radiation levels with less destructive effects on the land.
How is such a bomb as a mass casualty device unfair in war, it is not unfair, it is not any different than conventional bombs just much much larger in its desired effects.
What difference is there if in a conventional war you fight and kill a million enemy combatants with rifles, artillery, grenades, white phosphorus, whatever else gets deployed, tanks, planes, and loose a bunch of your own guys, or you kill the enemy combatants using one or two neutron bombs and save your side alive.
A US Army Colonel in intelligence I knew in church, talked with him about the first gulf war against Saddam Hussein. I asked him why we stopped the war.
He said it was like shooting ducks in a barrel. Too many Iraqi's were dying. Imagine that...their casualties were too high. So then we had to go to war again later and took him out. Meanwhile he got to torture his own people for a few more years. And now Iraq still is a disaster, a failed nation state.