The reconstruction on a 6.6-km section of a highway in northern China's Shanxi will be completed in August for a detour designed to protect a world cultural heritage site Yungang Grottos in Datong City from pollution, provincial transport authorities said Tuesday.

The project costs 83.3 million yuan (12.2 million US dollars).

The No. 339 provincial-level highway used to expose the cultural heritage site to exhaust pollution and loud traffic noise.

To protect the Grottos, the provincial government decided to reroute part of the highway. The project started in May.

According to Wang Zhiqiang, a senior researcher with the provincial Research Institute of Transport Science, the original section of the No. 339 highway will be used as an exclusive route to provide tourists with access to two-thirds of the grottos not previously accessible to the public.

The rerouting project is part of a comprehensive conservation program which is well under way for Yungang Grottos.

The program also includes an anti-seeping project that has been recently approved by provincial cultural relics protection authorities.

The project embraces anti-infiltration efforts for cave roofs, seeping water control and arrangements against rain flushing at cave eave.

Apart from weathering caves which mainly resulted from seeping water, the Yungang Grottos are also threatened by coal dust, as the world heritage site is at the heart of China's coal belt.

To this end, nearby factories have been relocated, five villages have moved and trees have been planted around the site.

Listed as a UNESCO World Cultural Heritage site in 2001, Yungang Grottos hold more than 50,000 1500-year old statues of Buddha.

(Xinhua News Agency July 7, 2009)