The orange alert is issued when the level of PM 2.5 particles the most harmful kind is expected to remain above 200 on the Air Quality Index for three consecutive days, Efe news reported.
An alert of this level implies a reduction in production for certain industries, as well as the suspension of work in certain construction points. It also results in the prohibition of the circulation of heavy vehicles.
Hebei is located in the heart of the northern plains of China, where smog is common in winter as a result of high concentrations of industrial emissions, limited air circulation and coal burning.
A specific action plan was designed that included the creation of a special agency in that region, where the industrial infrastructure is dominated by chemical industries.
Liu Youbin, ecology and environment ministry spokesman, said Tuesday at a press conference that "2020 is a key year" to complete the plan, and that "the success of this fall season and winter will be decisive to measure total achievements."
"There are many tasks planned, more than in the previous two years, which demonstrates the government's determination to win the fight against pollution," he said.
However, he warned that winter pollution is "more sensitive," and that the weather conditions this season are not going to be as favourable as in previous years, when high winds used to help disperse polluting particles.
Experts such as Lauri Myllyvirta, of international environmental organization Greenpeace, said there has been an effective reduction of pollution in the Beijing-Tianjin-Hebei region, but that it has increased in the south of the country, in provinces such as Jiangsu, Anhui, Canton and Fujian.
Chinese authorities announced in July that tax exemptions on purchases of vehicles running on renewables will continue until 2020 to "boost the country's ecological development."
( With inputs from IANS )