"Each building has its own blueprint of renovation to well protect its distinctive features," said Liu Yu, a construction engineer in charge from Tianjin Real Estate Appraise Survey & Design Institute on May 16.

At present, parts of the buildings are covered by protective screenings and scaffoldings in the old city of Lhasa radiated out from Barkhor Street, the most famous street for pilgrimage and business for the locals.

The final effect of renovation is unable to see right now.

During a recently held press conference, the protection project is open to the local residents, including how to keep the original appearance of the historical buildings and how to strictly follow the traditional Tibetan culture.

"In order to realize keeping the original appearance, photos of the historical buildings were taken and recorded, providing a reference and contrast method before the project started," said Ma Xinming, secretary of the publicity department of Lhasa.

"At present, the 172 historical building including 21 courtyards are renovated according to the effect picture of the designing scheme," said Liu Yu. "The final effect will be showed to the public after the project is completed."

The top official of Lhasa Cultural Relics Bureau is in charge of site supervision and coordination to solve the problems occurred in time in the course of construction.