Report: Environmental toll from land 'surgery' mounting

China's campaign to shave off mountaintops and fill in valleys to make way for cities may come at too high a price in the pollution, erosion and flooding unleashed by the unprecedented redistribution of earth, researchers warned.

Dozens of peaks up to 150 meters tall have been flattened to fill up valleys and create tens of square kilometers of land over the past decade. But there has been little assessment of the costs and environmental impact of these projects, researchers at Chang'an University said in a commentary published in the journal Nature this week.

"Land creation by cutting off hilltops and moving massive quantities of dirt is like performing major surgery on Earth's crust," the group said.