China is getting a $300 million loan from the Asian Development Bank to help clean up its smog-choked capital.

The ADB approved the loan Thursday to develop environmental and clean energy policies for Beijing, the neighboring port of Tianjin and surrounding Hebei province. The area is home to 109 million people.

The announcement came on the third day of a pollution emergency that prompted Beijing authorities to impose traffic restrictions and order factories to suspend operations.

"Poor air quality has reached such a serious level that it is jeopardizing the capital region's health and sustainable growth," Satoshi Ishii, an ADB urban development expert, said in a statement.

Hebei province is one of China's biggest consumers of coal, which authorities blamed for the spike in emissions of PM2.5, or particles smaller than 2.5 micrometers, which triggered this week's emergency measures.

The Manila-based ADB said policy work financed by its loan will include switching to cleaner energy sources, promoting public transportation and strengthening environmental enforcement.

The changes are forecast to reduce Hebei's annual coal consumption by 12.4 million tons, or 4 percent of its 2012 use, the bank said. It said carbon dioxide emissions also should decline.

The ADB said the KfW, a German government-supported development bank, also is expected to provide 150 million euros ($175 million) to the Hebei clean air work.