China has made huge strides in cleaning up its rivers and lakes over the past 15 years, suggesting clampdowns on pollution are working.
While major rivers such as the Yangtze still suffer from pollution, a comprehensive new study found that government policies since 2001 have significantly improved average inland water quality nationwide.
Between 2003 and 2017, the annual mean chemical oxygen demand (COD), a measure of the level of pollutants in the water, fell by 65 per cent. Levels of ammonia, which can run off from farmland, dropped more sharply, by 77 per cent. Dissolved oxygen, which shows how much oxygen is available to river life, improved by 14 per cent.
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The researchers also looked at discharges of pollution from factories, farms and other sources over the period, and found that reductions almost entirely explained the advances in water quality. 鈥淥ur results confirm the effectiveness of massive environmental efforts, notwithstanding rapid urbanisation and economic growth,鈥� says Ting Ma at the Institute of Geographical Sciences and Natural Resources Research in Beijing.
Independent Chinese experts said the findings supported , and that the state鈥檚 policies appear to be working. One example is a , which increased fines for polluters, says Sunan Shen at the Institute of Public and Environmental Affairs, who wasn鈥檛 involved in the study.
Still, difficulties remain. While pollution from industry and urban homes is down, discharges from rural homes have received less attention and rising pollution from livestock farming poses an 鈥渋ncreasing challenge鈥�, the authors say.
The clean-up is also inconsistent across the country. The biggest improvements in water quality came in the north and east of China, while changes were much more modest in the west. 聽Zhou Yongqiang at the Chinese Academy of Sciences, who wasn鈥檛 involved in the work, says those differences can be explained by the stronger economic growth in the east and north compared with the west. This has led to larger environmental investments in the east and north.
Nonetheless, the clean-up of China鈥檚 rivers and lakes is expected to continue. 鈥淭he Chinese central government launched ambitious ecological red lines and will invest more and more on environmental restoration in the near future,鈥� says Yongqiang.
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