‘‘They won’t even let us sing the national anthem,’’ Wang said. ‘‘They kept asking me who the leader of the protests was and I said that this is all voluntary. We have no leader.’’

In a sign that censors were at work, the name ‘‘Zhenhai’’ was blocked on China’s popular microblogging site Sina Weibo.

Protester Yu Yibing said he wanted the factory to be closed and his 7-year-old son to grow up in a clean environment.

‘‘As the common people, we need to live in a green environment. This is a reasonable request,’’ Yu said. ‘‘But the government only puts out some statement and refuses to see us and also suppresses us. I don’t know how else we can express our views.’’

The Zhenhai district government said in a short statement on its website Sunday evening that the project wouldn’t go ahead and that refining at the factory would stop for the time being while a scientific review is conducted.

Past environmental protests have targeted a waste-water pipeline in eastern China and a copper plant in west-central China. A week ago, hundreds protested for several days in a small town on China’s Hainan island over a coal-fired power plant.

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