What do we do without water? What happens when a city is unable to pump water for its residents? It seems an unlikely scenario for those of us who do not have to give a second thought to getting running water either at home or work.

However, for 3 million people in Harbin, Heilongjiang Province, the stopping of the city's water supply presented them with this nightmare problem.

The announcement was a shock to local residents, even though the municipal government at the same time outlined measures to guarantee enough bottled water at supermarkets, and made all wells across the city available for civil use.

Photos showed supermarket shelves empty of bottled water and residents carrying it home on their bicycles. Reports say that all drinks have sold out in some supermarkets.

The announcement by the local municipal government cited the possible contamination of water in the upper reaches of the Songhuajiang River in the next couple of days as the main reason for the water supply stoppage. A chemical plant explosion in the upper reaches of the river a week ago may have polluted the water, though water near the city has not been contaminated so far, the announcement said.

Whatever the cause of the water supply stoppage, we have enough reason to believe that no one in the city will die of thirst or even suffer from dehydration.

But residents' normal lives will undoubtedly be affected. The municipal education commission has already announced that primary and middle school students would stop going to school from November 24-29. Among other things, residents will not be able to bathe.

The possibility that the water has been contaminated by the chemical plant explosion has not been ruled out. This begs the question: What can we do to better prepare ourselves in case of an emergency such as a factory explosion?

There is always the possibility that any explosion and leakage of poisonous gas or liquid like the one last week will impact the environment and water of the surrounding area. We say preparedness averts peril. It should not be hard for authorities in charge to take into consideration the possible consequences should an accident happen. If the location of the factory had been away from the source of the river, millions of Harbin residents would not have been inconvenienced.

However, this lack of preparedness and foresight has become a frequent occurrence.

This reminds us of another possible water crisis, of an even larger scale. Most Chinese cities in the north are haunted by chronic water shortages. Projects like water diversion from the south or from the Yellow River have been launched to quench the thirst of these cities.

What if the rivers in the south do not have enough water for us to borrow when the diversion project is completed? Borrowing water from the south should be just one of the solutions to the problem. We should never put all our eggs into one basket.

What then are the other options? The authorities have repeatedly urged citizens to conserve water. But it is the responsibility of the authorities to spend money on water-saving facilities.

For example, if we had complete sewage treatment facilities installed and were able to treat 80 per cent of the waste water in the northern cities, and then we used the treated liquid to water flowers, wash cars and for industrial purposes, it is unlikely we would have felt such an urgent need to launch these money-guzzling water diversion projects.

We sincerely hope that water supply will soon resume in Harbin, and we also expect that decision-makers at various levels take all precautions possible to avert any peril before they pose real danger to residents.