World Water Day barely causes a ripple in Hong Kong. Heavily subsidised tariffs and a guaranteed supply from Guangdong ensure that we are more wasteful than thankful for the precious resource. There is barely a thought for having long showers, getting a bottle full from a shop rather than a household tap and preventing evaporation from reservoirs. Yet these are everyday matters for a large number of the world’s people, especially the 10 per cent of the global population, many living on the mainland, whose nearest supplies are unsafe.

Up to 80 per cent of Hong Kong’s water comes from the Dongjiang, or East River, an amount so plentiful and assured that there is no incentive to conserve. Household charges have not changed since 1995, making them among the world’s lowest. Supplies so cheap and plentiful make us oblivious to the growing water crisis on the mainland, where pollution, uneven distribution, urbanisation, desertification and climate change are worsening the plight of tens of millions. A water forum today at the Chinese University of Hong Kong and a Greenpeace report are among the few reminders of the seriousness of the problem.

Major lakes along the Yangtze are drying up. Management plans that involve building reservoirs make sense, but are causing tension with India and Mekong River countries that also rely on waterways that originate or flow through China for their needs. Competition for resources has been behind geopolitical conflicts in Africa and the Middle East. The UN estimates that about 650 million people do not have access to safe water, putting them at risk of infection and premature death.