that included targets for conserving populations of the endangered back-faced spoonbill. In 2019, 49 nests were built for the black-faced spoonbill on nearby uninhabited islands. There has also been conservation and rescue efforts targeting spotted seal populations. Dalian also maintains the National Spotted Seal Nature Reserve within Lioadong Bay. This reserve is home to a spotted seal population and is a breeding ground for multiple marine species. Environmental issues In 2001, the United Nations Environment Programme awarded the Dalian Municipal Government for its outstanding contribution to the protection of the environment. The average content of the four pollutants in the air reached Class II of National Ambient Air Quality Standards and there were 353 days with Air Pollution Index (API) over Class II (Good), including 108 excellent days with Class I (Superior). Dalian frequently ranks Grade 2 for air pollution according to State Environmental Protection Administration. However, the environmental effects of economic growth are of concern, according to Dalian Environmental Protection Agency, during the first half of 2011, respirable particles in the air increased significantly, with an average 40% higher than 2010. The water quality of offshore marine space remained stable overall. The annual average content of monitoring indicators for water quality met Class-II of the National Seawater Quality Standard, with the exception of Inorganic Nitrogen in Dalian Bay and the city's southern coast. The water quality of drinking water sources is considered good and complies with Class-III of Environmental Quality Standards for Surface Water.Recent events have had a major environmental impact on the city. In July 2010, the explosion of two petroleum pipelines released 11,000 barrels of oil into the Yellow Sea, according to official statements. Rick Steiner, an American marine conservationist working with Greenpeace, says that the figure could be upwards of 400,000. It was reported as the largest oil spill to occur in China, and involved 2,000 firefighters. The oil spill stretched for at least . 800 fishing boats were mobilized for the cleanup. The incident caused President Hu Jintao and Premier Wen Jiabao to intervene, and Vice Premier Zhang Dejiang moved in to help direct the rescue work. A researcher with the China Environmental Science Research Institute, said that "the impact on marine life and on humans – as the pollution enters the food chain – could last 10 years." This has compounded aquatic pollution, affecting the city's fishing industry. In August 2011, a dike protecting