Beijing is upgrading its air pollution warning and emergency response system.

Emergency response measures include an odd-even license plate rule for vehicles, shutdown and emission reduction of heavy polluters and suspension of school classes, according to the Beijing Municipal Bureau of Environmental Protection.

Starting in November, the warning system for Beijing, Tianjin and other heavy-polluted surrounding areas will boast three levels.

When the PM2.5 air quality index is set to go above 500 for three consecutive days, a level I warning will be issued. Level II is for 300 to 500 and III for 200 to 300.

The Beijing government outlined in early September its enhanced efforts to tackle air pollution over the next four years in the Beijing 2013-17 Clean Air Action Plan and on September 25 pledged to invest 1 trillion yuan ($163 billion) in clean air efforts.