Parts of N China under cover of smog on New Year's Day

A policeman wearing a mask is pictured on a smoggy morning in Zhengzhou, capital city of North China's Henan province, Jan 1, 2017. [Photo/IC]

BEIJING - Some areas in northern China including Beijing will pass New Year's Day under a cloud as the national observatory renewed an orange alert for air pollution on Sunday.

Heavy smog will persist in some parts of Beijing, Tianjin, Hebei, Shanxi, Henan, Shandong, Shaanxi, Hubei and Anhui from Sunday to Monday morning, according to the National Meteorological Center (NMC).

The northeast Liaoning and Jilin, central Hubei, and eastern Jiangsu will be hit by moderate smog.

China has a four-tier warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.

An orange alert means heavy pollution -- PM2.5 higher than 150 -- for three consecutive days.

When the alert is in force, outdoor activities in schools are canceled and construction work suspended.

Beijing issued an orange alert for air pollution on Thursday that will last till Sunday. Heavy polluting vehicles and trucks carrying construction waste are banned from roads and some manufacturing firms have cut production.

Outbreaks of smog are common in the winter in north China, where cold weather and burning of the dirty coal for heating combine to exacerbate the situation.

In a five-year plan on environmental improvements released on Dec 5, the State Council ordered strict control of the consumption of coal.