Spoilers/Setting: Set just before the start of New Who.
Ninth Doctor.
Summary: The Doctor doesn't always succeed in helping those who are in trouble.
The industrial revolution has done more damage to this planet than the advent of factories belching out pollution did on earth. The air is filled with smoke and smog, the rivers that haven’t dried up flow sluggishly, thick with stinking scum, decaying vegetation, and the bloated bodies of water creatures, while the land can no longer sustain crops.
All food has to be manufactured or imported, and fresh water is so expensive to produce that those who can’t afford it are slowly being poisoned, if they don’t die of thirst first.
The Doctor warned these people, but they wouldn’t listen.