The robot was the same size as a regular rat but resembled a simple plastic box on wheels.

Plastic straws are by no means the biggest source of plastic pollution, but they've recently come under fire because most people don't need them to drink with and, because of their small size and weight, they cannot be recycled.

Ochoa showed the journalists a black plastic lid that covered a swimming pool-size cement container of pig feces to prevent exposure to the outside air.