China's first deep-water drilling rig started operations in the South China Sea at 9: 38 am on Wednesday, marking "a substantial step" made by the country's deep-sea oil industry.

The sixth-generation semi-submersible CNOOC 981 began drilling in a sea area 320 km southeast of Hong Kong at a water depth of 1,500 meters, according to China National Offshore Oil Corp (CNOOC), the country's largest offshore oil producer.