From the Washington Post:

“It’s a Chinese rite of spring: The National People’s Congress gathers for its brief annual session, and police nationwide detain dissidents, religious activists and anyone else who might disrupt the pageantry of the figurehead parliament.

The stern reaction reflects the dilemma facing Hu’s government, which is promising more responsive rule but doesn’t want to give up its monopoly on power.”

washingtonpost.com: China Mobilizes to Silence Dissent