The Sewol ferry   was carrying 476 people, most of whom were students from a high school near Seoul, when it sank off South Korea's southern coast on April 16. Only 174 survived, including 22 of the 29 crew members. The sinking left more than 260 people dead with about 40 others still missing. On Tuesday, one ordinary diver died at a hospital, government spokesman Ko Myung-seok said. He is the first death among divers organized following the ferry's sinking, according to the coast guard. The 53-year-old diver was pulled to the surface by his teammates after losing communication about five minutes after he began underwater searches, Ko said. It was his first search attempt, Ko added. Despite his death, divers are continuing their searches for the remaining missing people. Ko said that divers had searched all those 64 areas at least once and plan to visit them again to look for more victims. Darkness, floating rubbish, bodies, and cabins on board have made the search difficult, and divers entered the last three unopened areas on Monday night, Ko said. Investigators have made their first arrests of people who were not on board the Sewol when it sank. The three people arrested on Friday and Sunday are accused of failure to handle of cargo on the ferry well. In all, 19 people have been arrested in the investigation , 15 of whom were crew members accused of abandoning passengers. A leader was arrested on suspicion of malpractice  related to company finances. Improper stowage  and overloading of cargo is suspected as a possible reason why the ferry sank. The ferry was carrying about 3,608 tons of cargo, more than three times what it could safely carry. A ferry loaded too heavily could lose its balance making even a small turn. The sinking has caused a national sadness. On Sunday 1.1 million people paid respects at 131 memorial sites around the nation, according to a governmental funeral support committee set up for the ferry victims. Monday was a holiday for Children's Day, but various events were canceled or put off because of the ferry's sinking. Tuesday was also a national holiday in South Korea for Buddha's Birthday, and more people are expected to visit those mourning stations. According to the investigation, the main causes of the ferry's sinking are   _  .
malpractice and wrong operations. wrong direction and sharp turning around too many students and crew members improper stowage and overloading of cargo