Hainan Airlines Hainan Airlines lands on Beijing International Airport after flying two hours from Shanghai, March 21, 2015. (Photo/New Express Daily)

Hainan Airlines has become the first Chinese airline to pilot a commercial passenger flight using biofuel produced from waste cooking oil known as "gutter oil," sparking heated debate across the country.

Flight HU7604 traveled two hours between Shanghai and Beijing on Saturday morning, powered by a "half-half" mixture of traditional jet fuel and biofuel developed from gutter oil.

Hainan Airlines says the fuel mix underwent a series of stringent safety examinations and tests by aviation authorities before obtaining official approval for the maiden flight, reported the Guangzhou-based Southern Metropolis Daily on Thursday.

"To put it simply, the quality of the fuel mixture must be equal to or even higher than conventional kerosene," the newspaper said, quoting an anonymous source from Hainan Airlines.

Statistics provided to the paper by China Petroleum and Chemical Corp (Sinopec), Asia's biggest oil refiner and the enterprise undertaking the biofuel R&D for Hainan Airlines' first green flight, show that China's annual output of gutter oil is over 30 million tons, but only about 2 million tons can be collected and recycled.

Li Yizhong, deputy director of the National Committee of the Chinese People's Political Consultative Conference's Economic Committee, said actual numbers can be much higher. China can produce about 4.5 million tons of recyclable waste oil annually, according to him.

The cost of producing biofuel from gutter oil is somewhere between 13,000 to 15,000 yuan ($2,100-2,400) a ton, while conventional jet fuel is priced at 8,000 yuan a ton, meaning the cost for the biofuel used on Hainan Airlines' recent flight was about two times the price of fossil fuel, the paper said.

Both Hainan Airlines and Sinopec say the oil mixture can gradually reduce carbon emissions by 35 percent, and also effectively reduce particle pollution. But that effect can be realized only if biofuel is in mass production and application, the chance of which is now dampened by high production costs.

Sinopec is calling on China to roll out supportive policies to encourage research, production and use of gutter oil-generated biofuel, the paper said.