1 in 7 Billion

“But we don't take up as much space as you'd think.
Standing shoulder to shoulder all 7 billion of us would fill the city of Los Angeles.
So it's not space we need – it's balance.”

What it means is we have a lot of space in the world, but if you look at some country's they don't have water. So what its saying is we need to stop wasting water and give it to people who need it. They have space.

910000 people don't have clean drinking water in the world.