(Yicai) May 27 -- More than 40 officials and senior executives in China's energy sector have been investigated for disciplinary and legal violations so far this year, as the country steps up efforts to combat corruption in the industry.

This month alone, at least nine officials and top executives have been put under investigation, according to official figures. The latest is Zhang Jinfeng, former chairman of Jilin Energy Investment Group, according to notices posted on the websites of the Central Commission for Discipline Inspection and the National Supervisory Commission on May 24.

Energy sector projects are capital-intensive, often involving investments in the hundreds of billions, which can easily lead to corruption, an industry insider told Yicai.

Also on May 24, a court in Jiangsu province announced that Cao Guangjing, former vice governor of Hubei province, had been found guilty of bribery, accepting assets worth over CNY200 million (USD27.6 million), and leaking insider information that resulted in illegal profits of more than CNY10.4 million (USD1.4 million).

Li Dong, former deputy general manager at China Energy Investment, accepted up to CNY108 million in bribes to illegally assist several entities and individuals, a court in Jiangxi province ruled last month.

Wang Jianshe, former chairman of the supervisory board of Jinneng Holding Group, is still under investigation for suspected serious disciplinary and legal breaches despite retiring many years ago.

Editor: Futura Costaglione