China's top legislature is reviewing the fourth draft amendment to the environmental protection law from Monday to Thursday.

Compared with the version tabled for a third reading in October, the latest amendment involves several changes to some controversial clauses.

These include asking authorities at county level and above to build up an environmental pollution public warning system.

They also include empowering environmental protection administration agencies at county level and above to freeze and seize property and machinery from enterprises causing severe pollution, and building up a daily penalty system for fining companies that violate the law.

The clause that has triggered the most controversy over the past two years concerns the type of organizations that should be granted the right to bring environmental lawsuits in the public interest.

In the fourth draft, social organizations registered with civil affairs bodies at prefecture level and above, which have been dedicated to environmental protection for at least five years and which have a good reputation, are qualified to initiate such lawsuits.

Under the previous draft, only environmental social organizations registered at the Civil Affairs Ministry had this right.

"The change may raise the number of qualified organizations from less than 100 to several hundred," said Ma Yong, director of the supervision and litigation department at the Environmental Legal Service Center of the All-China Environment Federation.

The federation is one of the most active organizations in the field of environmental public interest lawsuits.

The current Environmental Protection Law was enacted in 1989. The revision process has taken almost two years since the first draft in August 2012.

The Standing Committee of the National People's Congress, the country's top legislature, held second and third readings of the environmental protection law draft amendment last year, but no vote was taken.

Experts say it is highly likely that the fourth draft may be voted on and passed on Thursday.

"Completing the amendment is extremely urgent to respond to the call of the public," Ma said.