US-Mexico border wall poses 'severe environmental threat'

US-Mexico border wall poses 'severe environmental threat'

Bulldozers are clearing the way to build a new wall on the border between Mexico and the United States.

The wall is a $5bn commitment by US President Donald Trump to stop asylum seekers getting into the US.

But experts say the environmental cost of the wall may be enormous too, as well as irreversible.

Al Jazeera's Rob Reynolds reports from northern Mexico.