People try to plant trees wherever they want them. When plastic bags are destroyed,it does a lot of harm to the atmosphere.

1) People try to plant trees wherever they want them. Plants are planted (Present Indefinite Passive) by people wherever they are wanted (Present Indefinite Passive) by them. 2) When plastic bags are destroyed, it does a lot of harm to the atmosphere. A lot of harm is done (Present Indefinite Passive)  to the atmosphere when plastic bags are destroyed (Present Indefinite Passive).