China's civil aviation circle has gone through an unprecedented overhaul in which a number of officials and airline executives have been netted by the top anti-graft watchdog over the past five months.

In the latest high-profile case, Zhou Laizhen, 55, deputy director of the Civil Aviation Administration of China, is suspected of "severe violations" of Party discipline, the Central Commission for Discipline Inspection said in a brief statement on its website on Tuesday night. It did not give further information.

Zhou was in charge of the planning, financial and airport departments at the administration.

The Shandong native started his career with the Finance Ministry in 1981 after he graduated from Dongbei University of Finance and Economics in Dalian, Liaoning province. In October 2006 he was appointed head of the CAAC financial department. In March 2013, Zhou became deputy director of the administration.

Zhou's investigation follows a succession of probes into lower-level CAAC officials and industry executives since July, when a group of Party inspectors was sent to the administration to conduct a two-month disciplinary check.

Those caught by inspectors include Liu Dehua, assistant to the director of CAAC's Air Traffic Management Bureau, Shi Boli, general manager of Beijing Capital International Airport, and Si Xianmin, chairman of China Southern Airlines.

In the wake of their detention, speculation began to circulate among industry observers that a high-level official within CAAC was likely to be exposed soon.

Wang Huaichen, head of the inspectors sent to CAAC, told administration heads in October that the agency has been plagued by a host of problems such as cronyism, embezzlement of State funds and bribery.

He noted that inspectors have sent clues about some officials' misconduct to the CPC Central Commission for Discipline Inspection and other related authorities.

A source close to CAAC who wished not to be named told China Daily that he suspects Zhou was involved in the corruption case of Liu Dehua because both of them were responsible for financial affairs at CAAC.

"Moreover, Zhou was the one that oversaw civilian airport planning and construction at the administration, which means he was a key man when it comes to whether a new airport could be approved or not," he explained. "Considering local governments are eager to upgrade their airports or build new ones, you can understand how big this business is."

China now has 202 civilian airports, with 35 new ones being built and more than 60 existing ones undergoing expansion, Li Jiaxiang, director of CAAC, previously told reporters.

The government planned to invest 500 billion yuan ($78 billion) in 193 major domestic aviation projects before the end of this year, according to the CAAC.

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