BEIJING (AP) — Thousands of people in Shanghai who test positive for the coronavirus but have few or no symptoms are being ordered into quarantine centers in exhibition halls and other buildings.

The move is part of official efforts to contain China’s biggest coronavirus outbreak since the 2-year-old pandemic began.

Most of Shanghai was shut down starting March 28 after case numbers soared. The biggest quarantine center is in the National Exhibition and Convention Center, which has beds for 50,000 people.

One resident says lights there are left on all night, making it hard to sleep, and she has yet to find a hot shower.