By David Stanway, Philip Wen and Stella Qiu ANYANG/SANGPO, China (Reuters) - For years, China's industrial heartland has been cloaked in smog, its waterways choked with pollution pumped from enormous clusters of factories churning out the mountains of cement and steel needed to build the Chinese economy. Aiming to tackle what has become a huge public health problem, the authorities have cracked down on polluting industries, targeting provinces like Henan, which has a population of 100 million... Читать дальше...