Shanghai Port, the world's busiest container port, saw its container volume in July fall 1.8 percent from a year earlier, a rare contraction in activity, data issued by the port's operator showed.

Container throughput reached 2.84 million twenty-foot equivalent units (TEUs), down from 2.77 million in June.

The decline in throughput in July could bode ill for China's trade in July.

Trade data for July is due on Friday. According to economists polled by Reuters, export growth is expected to have slowed to 8.6 percent in July, down from 11.3 percent in June. (Reuters)