What is the first step to take to reduce pollution?

The answer would be to gain information about the current state of environment and ways to inprove it.

Stop littering on the ground , instead of recycling trash or burning it, shoot it into space far away from the milky way , or just stop making factories , that pollutes the earths air.  

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.