Beijing introduced new rules to deal with air pollution on Monday.
According to the city's environmental protection bureau, the new heavy air pollution emergency response program will replace the current version, launched on Oct. 2013.
Four-tier alerts--blue, yellow, orange and red--will be issued on "heavy pollution" days. Red alert, the highest, will be issued for heavy pollution that is expected to last more than three days. An air quality index of over 200 is defined as "heavy pollution".
Orange and red alerts will be issued 24 hours before the heavy pollution days, according to Yao Hui, deputy head of the bureau.
Drivers with odd and even license plates will be allowed on alternating days during red alerts.
Heavy vehicles including construction vehicles will be banned from the roads during orange or red alerts.
When an orange alert is issued, all the industrial factories will be closed except those necessary to maintain the operation of the city. Construction sites will be shut down.
In 2014, Beijing issued blue alert 11 times, yellow alert five times, and orange alerts twice.