BEIJING — China’s inshore seawater quality improved in 2016, according to data issued on June 29 by the Ministry of Environment Protection (MEP).

Among the 11 coastal provincial regions, Shanghai and Zhejiang were placed at the bottom of quality classification while Guangxi and Hainan were at the top.

The proportion of “excellent” quality increased while that of “inferior” quality was declining, said Liu Zhiquan with the MEP.

Substandard water was detected in Bohai Bay, at the mouths of the Yangtze River and Pearl River, in Liaodong Gulf and on southeastern coastlines, with inorganic nitrogen and reactive phosphate being the main pollutants, according to the ministry.

More than 90 percent of the 27 monitored bathing beaches reported excellent or good water quality, said Liu.

He said the ministry has increased monitoring sites from 301 to 419 at the end of 2015, covering inshore water in the country’s four marine areas.