Air pollution in parts of China is now so extreme it could lead to conditions similar to a “nuclear winter,” scientists say. The smog that covers the country has become so thick it is impeding photosynthesis, potentially disrupting China’s food supply. China’s pollution problem is reaching crisis point, with acrid smog covering six southern provinces for the past week. Over the last few days... 

People pay visit to the Temple of Heaven in Beijing on February 24, 2014. Air pollution strikes unhealthy levels in the Chinese capital Beijing for the sixth day in a row, prompting warnings for people to stay indoors. On Tuesday, officials said the gray smog that has been covering the sky in much of six northern provinces could last until Friday. Since last Friday, an orange alert — the second-highest...