MANILA—The Philippines’ defence minister on Tuesday ordered the military to investigate a report by a U.S.-based tech firm that hundreds of Chinese vessels were dumping sewage into contested areas of the South China Sea. China maintains a constant presence of coastguard and fishing boats in the South China Sea to assert its claim of sovereignty, including hundreds in the Spratly islands, where the Philippines, Brunei, Taiwan, Vietnam, and Malaysia also have claims. Simularity, an AI-based satellite image analysis firm, on July 12 made public satellite images collected over a five-year period that it said showed damage caused by untreated human waste from Chinese vessels. “While we are confirming and verifying these wastes being dumped … we consider such irresponsible acts, if true, to be gravely detrimental to the marine ecology in the area,” Philippine Defence Secretary Delfin Lorenzana said in a statement. “Despite conflicting claims and interests by states in …