KEY POINTS:
Chinese troops racing to drain an "earthquake lake" ahead of more rains made substantial progress digging a diversion channel and have created escape paths in case a mud and rock dam gives way.
The landslide-blocked river at Tangjiashan in Sichuan province is now the most pressing danger. If the build-up of water bursts through the dam formed by a landslide during the May 12 quake, 158,000 people downstream will have to move.
