CHONGQING - Southwest business hub Chongqing rolled out 33 projects on Monday to solicit private capital in the form of a public-private partnership (PPP).

These projects, worth a total of 130 billion yuan (21 billion U.S. dollars), include three highways, two subway lines, parking lots, hospitals, affordable housing and other urban infrastructure, according to a PPP project agreement signing ceremony on Monday.

Both domestic and foreign investors will take part in the construction and operation of these projects as the metropolis strives to lower government spending and improve public services.

The city is expected to implement PPP projects worth 800 billion yuan by 2020.

PPP was important in keeping an 18 percent growth in fixed asset investment in 2014 when the government cut 101.6 billion yuan in debt, according to Huang Qifan, mayor of Chongqing.

PPP refers to long-term cooperation between governments and private companies in infrastructure or public services. In most cases, PPP projects are funded and operated by private investors and supervised by local governments.

PPPs have existed in China since the 1980s, but the uptake of the financing mode has been slow.

Confronted with mounting local government debt and a pressing need to fund urbanization and cope with a rapidly aging population, China released two PPP guidelines in 2014.

In May, the State Council, China's cabinet, said the government will streamline approval procedures for PPPs and that PPPs in public services will enjoy tax breaks and other financial rewards.