As Beijing prepares to raise its car emission standards on Feb 1, neighboring areas have been using poorer quality fuel that threatens to undermine the capital's anti-pollution efforts, experts said.

Cities nationwide have been urged to adopt stricter automobile emission standards to ease the murky haze and improve air quality.

Hao Jiming, an academic at the Chinese Academy of Engineering, said that raising the quality of gasoline and diesel and emission standards is crucial to improving the air.