Although a clean water supply was restored two weeks later, what happened in those cities revealed a weakness in our mechanisms for preventing water pollution and ensuring safe drinking water.

The incident happened in the Tuojiang River, a main contributor of the country's longest river, the Yangtze, in late February.

Waste water from a local chemical plant broke through the monitoring networks and flowed into the river, contaminating the drinking water sources of cities along the stream.

As a result, the ammonia and nitrogen content in drinking water was more than 20 times the State safety standard. The highest was a shocking 152 times the standard. Tap water turned black and smelled of ammonia.

An investigation found that the chemical plant failed to undergo mandatory filter procedures before discharging its chemical-ridden waste water.

Those managers responsible for the accident will hopefully receive due punishment. But this is a crisis that should not end with just a slap on the wrist.

One problem that needs to be investigated further and reflected upon is how the contaminated water bypassed the monitoring network.

According to the investigation, on February 20, when the spill occurred, local tap water companies said the water "had no problem." These companies are supposed to conduct daily examination of drinking water sources.

The technical apparatuses were clearly less sensitive than the fish. At around that time, a large pool of fish began to mysteriously die.

Not even the local environmental protection and public health supervision departments detected any problems in the water.

They conducted sample analysis of the tap water on the ninth day of every month and still did not realize the water was polluted.

The problem was found on January 27, when an investigation team of higher authorities intervened, states an article in the Southern Weekend.

Without improving the working efficiency of those departments and filling the obvious loopholes, the lives of millions will continue to be placed in jeopardy, as it was in those three Sichuan cities.

Low efficiency has directly led to failed communication and slow reactions from the local government to control the situation.

It was not until January 27 that the municipal investigation team began to collect water samples to analyze the seriousness of the pollution.

On March 2, when results of the samples came out, the municipal government began to inform local people to stop drinking tap water.

It is reported that more than 500,000 kilograms of fish died and the direct economic losses are worth 100 million yuan (US$12 million).

The loss is nothing compared to the lives of those whose health has been affected. Local people had been drinking water that should not be drunk during the days after the water source was contaminated.

There has not been any statement on the number of people who fell ill because of the polluted water.

Officials, apart from factory managers, who are responsible, should be held accountable.

It is unsettling to hear a high-profile provincial official, quoted by Chengdu-based Huaxi Metropolis News, say that the managers of the chemical plant must be held accountable and related environmental protection departments must "engage in a deep retrospection."

Without a serious commitment to fulfil their duty of ensuring safe drinking water, the problem will not be solved.

Self-retrospection is far from enough.