The environment in Cubatão “Death's valley [the Valley of Death] in the 80s” -part 1 -The causes ¿effects? from of pollution

Between the 70s and 80s the pollution from industries [heavy industry] destroyed hills, forests,rivers and people in Cubatão. Trees were brown, and they death died, factories left smokes in the air, chemical products in rivers and in the ground. People had health problem and children were born without brains.
Cubatão became the most polluted city in the world, it was called “the valley of the death”.

Here are some different ways to write this.

Environment in Cubatão “Death's valley in 80's” -part 1 -The causes from pollution

Between the 70's and 80's the pollution from industries has destroyed hills, forests, rivers and people in Cubatão. Trees were left brown and dead, factories left smokes in the air, and chemical products infected rivers and the ground. People had health problems and children were born without brains.
Cubatão became the most polluted city in the world, it was called “the valley of the death”.

Environment in Cubatão “Death's valley in 80's” -part 1 -The causes from pollution

Between 70's and 80's the pollution from industries destroyed hills, forests,rivers and people in Cubatão. Trees were brown and they death, factories left smokes on the air, chemical products in rivers and ground. People had health problem and children were born without brain.
Cubatão became the most polluted city in the world, it was called “the valley of the death”.

'Between 70's and 80's' :  In the 70's and 80's

'they death' :  they died

'left smokes on the air' :  emitted smoke into the air / polluted the air with smoke

'chemical products in rivers and ground' :  and chemical products/waste in rivers and the ground

'health problem' :  health problems

'born without brain' :  born without a brain [anencephaly]

'the valley of the death' :  The Valley of Death

Environment in Cubatão “Death's valley in 80's” -part 1 -The causes from pollution

Between (the) 70's and 80's the pollution from industries destroyed hills, forests,rivers and people in Cubatão. (The) trees Trees were brown and they (died) death, factories left smokes on (in) the air, chemical products in rivers and (on the) ground. People had health problem(s) and children were born without brain(s).
Cubatão became the most polluted city in the world, it was called “the valley of the death”.("valley of death)