Hebei, a northern region with the worst air in China, faces an enormous challenge in cleaning up its dirty air as data showed that little more than one third of all days last year met quality standards.

The air quality index (AQI) in 129 days, 35.3 percent of days in 2013, was below 100, Chen Guoying, director of the Hebei provincial bureau of environmental protection, told a local legislature on Wednesday.

The province, which surrounds the national capital Beijing, had 80 days, or 21.9 percent, of severe air pollution (AQI readings higher than 200), Chen said.

According to statistics published monthly by the Ministry of Environmental Protection, Hebei is home to up to seven of the country's top 10 polluted cities.

"Heavy smog hit at the time of the "two sessions" in 2013 and again this year," said Liu Ronghua, a local political advisor, at a panel discussion at the annual meeting of the provincial people's political consultative conference.

The "two sessions" refer to the annual meetings of the local legislature and political consultative conference.

"Smog has triggered a survival crisis and people are wondering where is suitable to live. Some are fleeing big cities to avoid the toxic air," Liu said.

Hebei's economy is dominated by highly polluting and energy guzzling heavy industries, which contributed to up to 77 percent of all emissions into the air, according to Chen.

The three sectors of steel, petrochemicals and construction materials account for half of its industrial output. Hebei churned out 180.5 million tonnes of steel last year, the largest among all provincial-level regions, Chen said.

To tackle the severe air pollution, the provincial government has banned approvals of new steel, cement, glass and nonferrous metal plants.

Meanwhile, it has pledged to cut its annual steel and cement production capacities by 60 million tonnes respectively by 2017 and to reduce its annual coal consumption by 40 million tonnes from 2012 levels under the same time frame.

To meet the targets, authorities will encourage mergers and acquisitions and order closures or use pricing reforms to prompt outdated facilities to shut down.

Hebei has entered a period of painful economic transition and the government will focus more on environmental protection and greener growth rather than on pure gross domestic product expansion, said Zhang Qingwei, governor of Hebei.

The central government is becoming more serious in tackling pollution as the choking air has become the target of growing discontent among urban residents.

In September, the State Council, or the Cabinet, signed air pollution control initiatives with six provinces and municipalities in north China, including Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia and Shandong, in a coordinated effort to tackle severe air pollution.