More than 162 cubic meters of contaminated water were discharged into the Yangtze River estuary by a Panamanian-registered cargo ship, which was nabbed by the Shanghai Maritime Safety Administration on Jan 1.

The 2,282-ton liner discharged the poisonous and harmful waste into the Yangtze River four times on Nov 8 and Nov 25, according to a release by the administration.

Such discharges broke international conventions and China’s marine environmental management regulations on the prevention of pollution from ships.

The case is now under further investigation.

There were five similar cases caught last year by Shanghai maritime authority's Jinshan branch office, which tracked down the New Year's Day's case.

An aircraft from the Shanghai Maritime Safety Administration filmed an oil slick 600 meters long and 40 meters wide on a routine patrol Nov 3 over the Yangtze River, which was discharged from a foreign oil tanker.

Mariners from the vessel have denied the pollution discharge.