He defines pollutants as substances or microbes or harmful radium that cause living things diseases or lead to their death.
(He; defines; pollutants; as substances or microbes or harmful radium) (substances or microbes or harmful radium; cause; living things diseases) (substances or microbes or harmful radium; lead; to their death)
He substances or microbes or harmful radium substances or microbes or harmful radium
defines cause lead
pollutants as substances or microbes or harmful radium
living things diseases
to their death