BEIJING, May 13 (Xinhua) -- China Development Bank's (CDB) outstanding loans to the Yangtze River Economic Belt amounted to around 4 trillion yuan (about 589 billion U.S. dollars) by the end of March.

The CDB, the world's largest development finance institution, mainly deploys the loans to major projects in fields of environmental protection and restoration.

The bank has supported a series of projects in terms of controlling water contamination, restoring water ecology and protecting water resources in some provinces including Hubei, Guizhou, Jiangxi and Yunnan.

The loans also involve other projects of infrastructure connectivity and industrial transformation and upgrading, according to the bank.

China issued a development plan for the Yangtze River Economic Belt in September 2016 and a guideline for green development of the belt in 2017.

The Yangtze River Economic Belt consists of nine provinces and two municipalities that cover roughly one-fifth of China's land. It has a population of 600 million and generates more than 40 percent of the country's GDP.