A man wears a face mask while walking on the Bund during a hazy day in downtown Shanghai in this 2013 file photo. [Photo/Agencies]

BEIJING -- China will tighten management over environment monitoring agencies in a bid to ensure legitimate, transparent data.

Agencies engaged in environment monitoring, both government- and non-governmental entities, must operate within the law, adhere to technical standards and be responsible for the authenticity and accuracy of their data, according to a document released by the State Council on Wednesday.

Environmental authorities will seriously punish those breaking rules or falsifying data, it said.

Regarding what has been described as "chaotic environmental information" released from different channels and by different standards, the government said it would establish a national environment monitoring network by 2020 for the unified release of environmental data.

The Ministry of Environmental Protection will look into local governments involvement in environment monitoring to reduce interference. Some local governments have manipulated environmental data as pollution levels are linked to performance reviews.