Xi'an, the largest metropolis in northwest China, is expected to invest 2.7 billion yuan (325 million US dollars) in infrastructure projects this year, doubling last year's figure, or the record sum in its history.

The funds will be used to build Heishuihe (black brook river) water control project, the second citywide ring road, a key sewage treatment project, a gas network in urban area and an elevated expressway, expand a drinking water pipeline, widen major avenues and beautify some 10 street squares.

The move is part of the city's effort to turn this ancient tourist city into an international metropolis and prepare for an upsurge of economic growth in western part of China. Xi'an, the starting point of the renowned ancient Silk Road, now serves as a bridgehead of economic development in western China.