LHASA, Feb. 21 (Xinhua) -- A total of 49 sewage treatment plants are under construction in the Tibet Autonomous Region, in an effort to better protect "Asia's water tower" -- the Qinghai-Tibet Plateau.

Construction of 25 plants was started this year, with a total investment of 630 million yuan (93 million U. S. dollars). The plants are located in 19 counties and six towns, two of which are at an altitude higher than 4,000 meters.

Sonam Nyima, head of the regional housing and urban-rural development department, said Tibet has a fragile eco-system. The sewage plants will greatly improve the region's sewage treatment ability. Low cost, low energy consumption and high-efficiency technologies will be used in the plants.

In 2010, Tibet's first sewage treatment plant was put into use in Qamdo. Currently, the region has finished building 16 sewage treatment plants.