A woman wears a mask as she visits Tiananmen Square in Beijing Sunday, Jan. 13, 2013. People refused to venture outdoors and buildings disappeared into Beijing's murky skyline on Sunday

 

              A woman wears a mask as she visits Tiananmen Square in Beijing Sunday, Jan. 13, 2013. People refused to venture outdoors and buildings disappeared into Beijing
A woman wears a mask as she visits Tiananmen Square in Beijing Sunday, Jan. 13, 2013. People refused to venture outdoors and buildings disappeared into Beijing's murky skyline on Sunday as the capital's air quality went off the index. (AP Photo/Ng Han Guan)
Tags: Outdoors