China to issue air pollution warnings in Beijing, Tianjin BEIJING, Oct. 1 (Xinhua) -- China plans to pilot an air quality warning system in the heavily-polluted cities of Beijing, Tianjin and surrounding areas next month amid the country's increasing efforts to tackle the much-concerned problem. China Meteorological Administration and the Ministry of Environmental Protection has jointly released the plan that put the alert system at three levels -- I being the highest and III the lowest. When the air quality index is set to go beyond 500, a level I warning will issued, and level II and III are for the index to be at between 300 to 500, 200 to 300, respectively, for three consecutive days. The plan came as China has been under growing pressure to address the causes of air pollution after heavy smog smothered large swathes of the country early this year. The government aims to cut the density of inhalable particulate matter by at least 10 percent in major cities nationwide by 2017. PM 2.5, a key indicator of air pollution, should fall by about 25 percent from 2012 levels in Beijing and surrounding provincial areas by 2017, according to a recent government plan.