BEIJING, Sept. 16 (Xinhua) -- China's State Council has issued a guideline to improve urban infrastructure, according to a statement posted on the government's website on Monday.

Underground construction should come before construction above ground, the statement said.

Besides government input, non-government capital will be encouraged to partly join construction or management of the projects so as to improve the ecological environment and safety in cities, it added.

The guideline specifies key tasks to upgrade urban infrastructure.

One is to improve construction and renovation of the underground pipe network, including pipes for water, sewage, rain, gas, heat and communication.

By 2015, 73,000 km of sewage pipes should be added, and 80,000 km of old urban gas piping and 92,800 km of old urban heat piping should be renovated, under the guideline.

Another task is to boost infrastructure for urban sewer works and flood-fighting. A relatively complete system on drainage and flood-fighting should be built in about 10 years.

A third task is to boost infrastructure to deal with sewage and garbage treatment.

By 2015, at least 85 percent of urban polluted water should be treated and about 90 percent of everyday garbage should have been made harmless, the statement said.

A fourth point is to boost urban traffic infrastructure. Underground railways should play a key role in public traffic. By 2015, the country will add 1,000 km of rails for transport.

A fifth task concerns construction of the urban power grid and a sixth task is to build more urban ecological parks.

By 2015, each city should have at least one park as a disaster shelter with sufficient equipment, the plan instructs.

China is undergoing fast urbanization. Its urban population hit 690 million, 51.27 percent of its total population in 2011, the first time that more Chinese have lived in cities than in the countryside.