The top official in coal-rich Datong city in Shanxi province is being investigated on suspicion of graft, as the country ramps up its efforts to clean up government.

China's top anti-graft body said on Wednesday that Feng Lixiang, 57, Party chief of the city, was placed under investigation for "suspected grave violations of Party discipline", a phrase often used to refer to corruption.

Not including Feng, one-third of the top provincial decision-making body and a total of more than 30 officials in the province have been investigated for corruption since the central government launched the anti-graft campaign in late 2012.

The most recent official in the city being prosecuted for taking bribes is former deputy mayor Jin Ruilin, according to the Supreme People's Procuratorate.

Datong is a major coal mining city. The Datong Coal Mine Group, China's third-largest State-owned coal producer, is based there.

Xue Lan, a professor at Tsinghua University's School of Public Policy and Management, said local government officials have opportunities to gain personal benefits from the highly lucrative coal mining industry, as they have the authority to approve projects and decide on development plans.

Over the past decade, the province has begun reform of the coal industry. Because government officials have the power to influence distribution procedures as well as prices, they are prone to corruption, Xue said.

He said the province is still faced with the serious challenge of fighting corruption, as five members of the 13-person provincial Party committee's standing committee were investigated recently for abuse of power.

"In the province with the nation's largest coal reserves, there is urgent need to build transparency in policymaking procedures and for a supervision mechanism to prevent misconduct in developing public resources," he added.

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