This is how commentators have defined the development gap between Beijing and its economically backward neighbor, Hebei province.

The nation's latest drive to integrate development of Beijing, Tianjin and Hebei brings some hope of narrowing that development gap and, in return, will facilitate Beijing's move to reduce pollution and improve environment.

If central government policymakers want to kill two birds with one stone, however, they must change their mindset and put Hebei's long-term and sustainable development on top of their agenda.

For decades, Hebei has been taken as a convenient source of resources for Beijing, which consumes water, coal and other resource products heavily.

As China's economy develops, the functions in Beijing have been restructured, with more focus put on clean industries such as high technology and clean energy, and environmental protection.

Hebei, however, has lagged behind in the clean drive and still heavily depends on heavy industries, such as steel-making, which cause environmental problems that have spilled over to affect Beijing. For example, it has been found the infamous smog shrouding Beijing has been partly caused by Hebei's industries.