How do plastic bags harm the environment?

Plastic bags have led to negative impacts on: animals, plants, and the environment.

Decomposed Plastics → Comes out as“plastic dust" → Contaminates animal life, the soil and water (including oceans and seas).

Animals

• Animals likely mistake plastic bags as food. When they ingest plastic bags, it obstructs their digestive systems and they eventually die.
• Meanwhile, Birds become trapped in plastic bags and marine animals also entangled in them and suffocate or starve to death. 
• After animals die, their bodies decompose and the plastic is released back into the environment again, which is a vicious circle of killing other living organisms again. 

Plants

• When plastic bags are littered, plant life on land is smothered and killed.
• In the ocean, plastic bags mostly sink to the bottom, which smothers marine plant life and kills them. 

Thus, when the number of animals and plants has decreased to a certain number, it interrupts the food chain and eventually, the ecosystem.