In March, the CAS began a remote sensing survey of the environment restoration in the worst hit townships of Wenchuan County in southwest China's Sichuan Province, hit by a 8.0-magnitude quake in May, 2008.

The survey showed that landslide areas have been covered by vegetation and that landslides have decreased in the monitoring areas.

However, there are still geological disaster risks including landslides in some areas.

The CAS surveyed the sites of 36 barrier lakes and found that 30 have completely disappeared, but that the dams of other six barrier lakes are stable.

The crisis of barrier lakes is over, according to the CAS, and the environment has improved. A barrier lake in Tangjiashan has been transformed into tourist destination and reservoir.

Of the areas surveyed 61 percent have much more vegetation, compared with ten years ago. And 63 percent have less soil erosion.

Optical and microwave cameras were attached to drones during the survey. (Xinhua)