(Reuters) - The government of the industrial city of Tianjin in northern China will limit the number of vehicles allowed on roads during heavy smog, state media reported on Monday, in the latest attempt to fight pollution.

On days of severe pollution, Tianjin will halve the number of vehicles allowed on roads by restricting licence plate numbers, as well as halt construction and manufacturing activity, close schools for the day, and halt large-scale outdoor activities, the official Xinhua news agency said.

China has vowed to reverse the damage done to its environment by decades of untrammeled economic growth, and has identified the region of Beijing, Hebei and Tianjin as one of the key targets of a programme to curb big industries like steel, thermal power and cement, all major sources of smog.

About one third of the pollution in Beijing, whose often choking smog has been dubbed the "airpocalypse", comes from outside the city, a pollution watchdog said last month.

Last month Tianjin banned new steel and cement plants, following similar statements from neighboring Hebei province and Beijing, and in line with a central government plan last year to restrict new manufacturing in key industrial centers.

Economic growth has long topped China's political agenda. But public anger over pollution has sparked protests and the government has now vowed to impose its will and make cleaning up the environment its priority. Even so, authorities often struggle to bring big polluting industries and growth-obsessed local authorities to heel.