BEIJING -- China will start a second national census of pollution sources this year, around 10 years after the first one, the Ministry of Ecology and Environment has said.

"The census marks the fundamental work of the country's environmental protection," Hong Yaxiong, director of the office in charge of the census, told a press conference on Thursday.

Major pollution sources will be archived and put into database, as part of the evidence for policy makers to monitor and improve environment, as well as prevent risks, he said.

The work to investigate the scale, structure and distribution of pollution sources will be completed this year and the results will be made available next year.

A preliminary survey has found about 7.4 million industrial and 1 million agriculture pollution sources, as well as mounting residential sources.

China published the results of the first national census in 2010, which targeted nearly 6 million industrial, agricultural and residential sources and centralized pollution control facilities, collecting 1.1 billion items of basic data.