A seven-year-old boy drowned yesterday in a swimming pool at a private estate at Ma On Shan. And a teenager is in a serious condition after almost drowning at the Victoria Park pool in the morning. The deadly accident happened at 5pm when the boy, surnamed Law, went swimming at a pool in the Monte Vista club house in Sha On Street. He was accompanied by his mother, an uncle and other children. About two hours into their swim, the boy's mother, 49, realised her son was missing when she came out of a changing room. He was seen at the bottom of the pool and was dragged out the water by his mother and the lifeguard. The boy was taken to Prince of Wales Hospital but was certified dead about 6pm. Investigations into the incident continued last night. Meanwhile, a boy, 14, was in a serious condition after apparently blacking out during a breath-holding competition with his friends in the Victoria Park Swimming Pool in Causeway Bay. The boy, surnamed Hui, went to the pool at 8am with three of his friends after playing soccer nearby. They went to the deep end and began holding their breath, despite receiving warnings from lifeguards. While his friends returned to the surface, the boy continued to sit on the bottom. His friends thought he was still holding his breath but soon realised he had passed out. He was not breathing when a lifeguard dragged him to the surface, but he revived after resuscitation. He was in serious condition in Ruttonjee Hospital last night. Yesterday's accidents come after a six-year-old girl drowned in a South Horizons swimming pool on April 3. After last month's accident, the Leisure and Cultural Services Department warned swimmers to pay better attention to their abilities in the water.