Beijing and other cities across northern and central China were shrouded in thick smog Monday, prompting authorities to delay dozens of flights and close highways. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. Beijing’s smog had initially been forecast to lift by Monday. The “orange alert” is the third level, preceding a “red alert,” in China’s four-tiered warning system. On Sunday, 25 cities in China issued “red alerts” for smog, which triggers orders to close factories, schools and construction sites. Air pollution readings in northern Chinese cities were many times above the World Health Organization-designated safe level of 25 micrograms per cubic meter of PM 2.5, the tiny, toxic particles that damage lung tissue. The readings exceeded 400 by Monday afternoon in several cities in the northern province of Hebei. Expressways in Shijiazhuang, […]