China's severe environmental problems and government pledges to fix them have dominated the start of the country's closely watched annual legislative meeting this week, as leaders try to ease public worries about air, water and soil contamination that threatens to derail China's economic rise.

Two days into the session of the National People's Congress in Beijing, Chinese President Xi Jinping pledged to "punish, with an iron hand, any violators who destroy the ecology or environment, with no exceptions," according to the official Xinhua News Agency.

The environmental focus reflects worries that public anger over hazardous pollution could threaten the grip of the ruling Communist Party.

In another show of concern, Chinese censors began blocking a popular documentary released a week ago that lays out cost of the environmental crisis.