A heavily polluted river in Zhugao in China’s south-west Sichuan province PETER PARKS/AFP via Getty Images

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 …