Adviser: Cleanse oil industry of Zhou's influence

Disgraced former senior Party official Zhou Yongkang had "caused considerable damage to the cause of our Party and our country" and severely undermined the corporate culture in the oil industry, a former oil official said at a news conference on the sidelines of the annual legislative session.

Zhou was caught by the anti-corruption campaign and sentenced to life imprisonment last year for accepting bribes, abusing his power and deliberately disclosing State secrets.

He had worked as an oil industry technician long before rising to the Standing Committee of the Political Bureau of the Communist Party of China Central Committee, the Party's top leadership. He was believed to wield considerable influence in the industry till his investigation in 2014.