Big Chinese cities including Shanghai, Hangzhou, Nanjing and Wuhan are working to build ventilated corridors that will allow wind to disperse dirty air.

At the beginning of this year, Nanjing's Plan of Action for Air Pollution Prevention and Control unveiled a timetable for building clean-air corridors by the end of 2014.

Experts say ventilated corridors can bring fresh air from suburbs and disperse hot air that clogs city centers.

In many cities, tall buildings and dense layouts have increasingly encroached on ecological conservation areas that help purify air, compounding the haze problem.

"We need to learn from the German Ruhr area, by building cushion areas around industrial clusters," said Xu Xiaotie, an official at Nanjing's Environmental Protection Bureau.

Nanjing is also eager to improve its urban planning in order to diffuse dirty air. The city plans to move polluting factories out of its existing six ventilation corridors by the end of 2017.

Shanghai employed the corridor idea when constructing Century Avenue in Pudong New District. The corridor takes advantage of summer breezes from the southeast and winter winds from the northwest.

Last year, Wuhan was the first city to initiate an evaluation of its meteorological and geological conditions for building wind passages.

Cui Kai, from the Academy of Engineering, says these moves show that cities are paying more attention to energy-saving designs that were once neglected in urban planning.

Dong Wei, an architecture professor at Southeast University, has called for stronger enforcement of such plans. Dong said cities like Beijing and Nanjing considered building wind corridors, but ended up replacing them with modern buildings.