Beijing smog triggers red alert for 2nd time this month

Smog in China's capital Beijing climbed back into the unhealthy range on Saturday as the second pollution red alert of the month went into effect.

A wave of smog settled over the city of 22.5 million overnight and is forecast to last into Tuesday because of a lack of strong winds.

Levels of PM2.5, the smallest and deadliest airborne particles, rose as high as 303 in some parts of the city and are predicted to top 500 in coming days. That is more than 20 times the level that is considered safe by the World Health Organization.