China on Tuesday issued its first national census of pollution sources, with datas showing that the country's wastewater discharge totalled more than 209 billion tonnes while waste gas emissions topped 63.7 trillion cubic meters in 2007.

The result was announced at a press conference held at the State Council Information Office Tuesday morning.

"The census of pollution sources for the first time in the country is a significant survey on national situation. Its operations went smoothly and its main tasks were basically completed," said Zhang Lijun, Vice Minister of Environmental Protection, at the conference.

The census targeted nearly 6 million objects of industrial sources, agricultural sources, residential sources and centralized pollution control facilities, collecting 1.1 billion basic data on pollution sources.

Industrial pollutant discharges mainly concentrated in a small number of industries and areas, with prominent structural problems, Zhang quoted the census as saying.

Agricultural sources had notable influence on the country's water environment, therefore the prevention and control on agriculture source pollution must be placed into the environmental protection agenda so as to fundamentally solve the issue of water pollution, Zhang said.

According to Zhang, a database for the census was established covering environment-related information of nearly 6 million objects nationwide as gists for administration and policymaking.

It took more than two years for over 570,000 staff to finish the census since the State Council made the decision in 2006 and the central government allocated 737 million (about 100 million U.S. dollars) for the project in 2007.

China faces big challenge of environmental deterioration amid its rapid economic development. Environmental experts had suggested that trustworthy statistics on the sources and extent of pollution was highly necessary for the country's effective and long-term pollution prevention and control.