During China's National People's Congress in Beijing last month, President Xi Jinping threw down the gauntlet on cleaning up pollution. "We are going to punish, with an iron hand, any violators who destroy the ecology or environment," he said, "with no exceptions."

Environmental experts in Washington on Tuesday offered some ideas.

Public interest litigation (PIL), legal action undertaken to effect change in public policies, could be "one area for further development or improvement", said Jay Monteverde, program manager at the American Bar Association Rule of Law Initiative's Beijing Office, at a panel discussion at the Wilson Center.

"PIL should integrate more into government enforcement framework," Monteverde said.

According to China's revised Environmental Protection Law (EPL), citizens, lawyers and organizations "have the rights to obtain environmental information and participate in and oversee environmental protection", he said.

The new EPL, which went into effect on Jan 1, 2015, says that environmental protection functionaries at all levels "shall, according to the law, disclose environmental information, and improve the procedures for public engagement, to facilitate the participation in and oversight of environmental protection by citizens, legal persons, and other organizations".

The two major issues featured at the NPC in March were tightening the environmental "red lines" that control pollution and the central government's commitment to improving people's participation in the effective management of pollution.

Zhang Jingjing, an environmental lawyer and former director of litigation at the Center for Legal Assistance to Pollution Victims in China, said well-developed civil society organizations and an independent court system would help ensure that [PIL] litigation would work.

"China has made some progress with more environmental cases accepted by the court," Zhang said. "Public litigation work could be further accomplished with the help of proper economic incentives, elimination of barriers to case filings and increasing NGO works."

Chen Jining, an environmental scientist and former president of Tsinghua University who took office as minister of environmental protection last month, pledged tougher environmental law enforcement, innovation and market leverage to help ease the conflict between development and the environment.

He said that China would strengthen implementation of the revised environmental protection law and improve pollution controls, and cooperate with other nations.

China now provides about 30 to 40 percent of the funds for environmental protection. It allocated more than $4 billion to deal with rural pollution at the end of 2014, affecting 59,000 villages and benefiting 110 million people. The market for environmental protection in China will be worth around $1.5 trillion over the next few years, according to Chen.

Sheng Yang in Washington contributed to this story.