BEIJING—China's government is facing stiff resistance from sprawling state-owned corporations and local interests in its bid to combat air pollution, in an early test for the nation's new leaders following some of the worst air-quality days in recent memory.

A consequence of decades of breakneck growth, China's deep environmental problems are now seen as a potential obstacle to strong economic development, with concerns ranging from air pollution and water use to increasing consumption of fossil fuels. China's environmental...