BEIJING - China's top economic planner approved 21 fixed-asset investment projects with total investment reaching 54.1 billion yuan ($8.3 billion) in January, an official said on Wednesday.

The projects covered water conservancy, transportation, technology and energy, said National Development and Reform Commission spokesperson Zhao Chenxin at a press conference.

Those projects will help coordinate regional development as well as strengthening water conservancy and transportation infrastructure and expanding electricity network coverage, Zhao said.

The annual growth of China's urban fixed-asset investment, once a key driver of the economy, continued to cool in 2015 to 10 percent year on year, down from 15.7 percent in 2014, according to the official data.

The investment slowdown is believed to be one of the main reasons behind the weakness in demand and the downside risk to the Chinese economy.

There were a few bright spots, however. Fixed-asset investment in agricultural jumped 31.8 percent year on year. It was followed by 10.6-percent growth for the service sector and 8 percent for the industrial sector.