China established four-tier level of emergency plan in order to monitor pollution level in October 2013. Last week, Beijing escalated its pollution emergency level to red alert, the highest level of alert. In the red alert, a car restristiction is applied, construction projects and industrial plants are forbidden in order to reduce pollution level.

According to BBC, the Chinese capital announced red alert, the highest possible warning level, was issued late Monday, December 7 and will last until midday on Thursday, December 10. Limits have been placed on car use and some factories have been ordered to stop operations, as the pollution level according to air pollution monitor in Beijing reporting that intensity of tiny particles is at 291. The level of pollution is measured using the Air Quality Index (AQI).

Air Quality Index is an index for reporting daily air quality, based on the level pollutant particle in the air and its health effect. The higher the AQI value, the greater the air pollution level and the greater the health concern. Safety area of AQI are on the 0-50 level, while level above 200 is considered as heavily polluted and people should remain indoors.

China monitor its pollution level based on the content of six pollutants, including sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone and two suspended particles. The Ministry of Environmental Protection (MEP) is responsible for monitoring the air quality, and currently measuring the air quality in 163 major cities in mainland China.

China Daily reported that during that time, the Air Quality Index (AQI)  in almost all monitoing stations all across Beijing recorded more than 200. People are advised to stay indor due to a very heavy smog. Beijing's  worst air pollution was recorded on November 30 when the AQI reached 500.

Based on the emergency-plan for pollution level that was drawn up in October 2013, when the AQI surpass 200 for three consecutive days, the red alert is in effect. All school activities is advised to be suspended during the red alert period, as Beijing Education Commission sent a notice on Monday night to all middle, primary schools and kindergartens. Car restriction is also applied and two million people is expected to leave their car and use public transportation.

In the aftermath of the air pollution red alert, Xinhua reported that according to Ministry of Environmental Protection on Monday, December 14, heavy and chemical industries were the main offenders implicated in the recent smog across north China. Moreover, the coal energy takes up 90% of energy consumption in the Northern China, including in Beijing and Tianjin.

As the red alert has been lifted, China must increase its environment protection and replace the coal energy consumption with green energy.