How can transparency and better information disclosure help solve the heavy metal pollution problem China is facing today? The cadmium pollution incident in the Guangxi Zhuang autonomous region provides a vivid example.

According to news reports, industrial waste discharges, containing high levels of cadmium, contaminated a 100-kilometer stretch of the Longjiang and Liujiang rivers in southern Guangxi in mid-January. The first signs of the spill came after mass death of fish in the river. The pollution is now flowing toward Liuzhou, a city of 3.7 million people.

On Jan 23, the Liuzhou government began releasing data on the cadmium levels in the Liujiang River almost on an hourly basis. The government harnessed modern communication tools, even the social media, to disseminate information. The media widely applauded the move and praised the officials for their transparency during an environmental disaster.

In sharp contrast to the Liuzhou government's approach is that of the local government of Hechi, where the pollution originated. Cadmium pollution was reportedly detected in Hechi as early as Jan 15. But the Hechi local government did not notify its counterpart downstream, Liuzhou, until Jan 18. Worse, no specific information was made public by the Hechi officials except for an official media release on Jan 19.

This lack of concrete, reliable information from Hechi seriously impeded disaster relief efforts by city officials downstream. Also, secrecy fanned the flames of panic, which was illustrated in people's mad rush to supermarkets to buy bottled water after the scandal hit the headlines.

The real power of information disclosure, however, goes way beyond disaster relief. It can do a lot more to prevent disasters. The cadmium pollution incident unveiled the weaknesses of day-to-day supervision over polluting industrial facilities. Information disclosure can play a key role in strengthening this aspect.

In an era of booming resource-intensive industries, such as mining and smelting, China's environmental protection apparatus seems barely able to keep up in terms of monitoring and inspection capacity. The difficulty that the Hechi government had in identifying and confirming the exact source of cadmium pollution shows that supervision was at best inadequate before the incident.

As early as 2009, after a series of lead pollution cases, the Ministry of Environmental Protection had called for a "blanket inspection" of heavy metal pollution facilities. This means, in theory, local governments should already have an inventory of local industrial facilities that release heavy metals, with basic information on who is discharging what.

With such information in hand, a local government should be able to quickly pinpoint a source of pollution when it sees an unusual increase in the monitoring data of certain pollutants. This apparently did not happen in the case of Guangxi and the Liujiang River. Media reports show that local environmental inspectors were not even sure where the wastewater went in some suspected facilities.

It is clear that the government's environmental protection apparatus, low in capacity and short in manpower, cannot fight this battle alone. The public, especially non-governmental organizations (NGOs) working for the protection of the environment, has a role in contributing to such efforts.

But information disclosure is a must for the public to participate effectively. With basic information on where the polluting facilities are and what they discharge, the public can help environmental protection bureaus keep an eye on the performance of certain companies and even pressure the facilities to improve their environmental performance by leveraging their buyers or financiers. This has already been proven to work.

Some officials may fear that making too much pollution information public could trigger panic among people. But results from a recent initiative by the Ministry of Environmental Protection should be able to dispel such concerns. In August 2011, the ministry made an unprecedented move by releasing detailed pollution information on more than 1,900 lead-acid battery facilities across the country. It was the first time that information on an entire industry's environmental performance was made public.

Reactions to the initiative were overwhelmingly positive. A close scrutiny of the data by the media, environmental NGOs and the public resulted in corrections and a dataset of improved quality, which would only help the ministry to better supervise the listed facilities. Updated data were released again to the public in November. But no panic followed. Instead, what we got were improved data and an empowered public.

Environmental information disclosure is credited for having helped many industrialized countries achieve significant reduction in toxic releases. Systems such as the US Toxics Release Inventory incur only minimal administrative cost, but are highly effective. There is no reason why China, still exploring ways to rein in rampant pollution, should not make use of such readily available instruments.

The author is Greenpeace East Asia's toxics campaign head.