LANZHOU, March 19 (Xinhua) -- China's oil giant, the China National Petroleum Corporation (CNPC), has started a major environmental protection project in its northwestern Lanzhou branch to prevent water pollution.

    ;The CNPC will invest 1.5 billion yuan (187.5 million U.S. dollars) in the project in Lanzhou, capital of Gansu Province, over the next three years, company officials said.

    A buffer zone including over 20 km of pipelines and four pools with a total capacity of 300,000 cubic meters will be built to contain possible spill of polluted water.

    The CNPC will invest 500 million yuan (62.5 million dollars) this year in the project, and an aquatic amusement park will be turned into one of the pools starting from July 1.

    The project means the second longest river in China, the Yellow River, is safe from pollution by the CNPC branch.

    The Songhua River in northeast China suffered major pollution in November when around 100 tons of pollutants containing hazardous benzene spilled into it after a chemical plant explosionin Jilin Province.

    The incident forced cities along the river, including Harbin, capital of Heilongjiang Province and a city of more than three million people, to temporarily suspend water supply. Enditem