The number of coal-carrying vessels from Sichuan province via the Three Gorges that have to lighten in Yichang has increased dramatically since a compulsory lightening rule was enforced on 11 November, according to the Yangtze Maritime Safety Authorities (MSA).

The Three Gorges Dam has increased water levels in the upper reaches of the Yangtze, but the current severe drought in Yichang and other parts of the middle reaches means that all vessels sailing via the reservoir have to lighten in order to sail through safely. They are required to have a draught of 2.8 metres or less, except those carrying dangerous goods that must have a draught of 2.7 metres or less.

By 27 November, 227 coal-carrying vessels had been lightened by a cumulative amount of nearly 190,000 tons. By activating a monitoring station on top of the Yichang-Wanzhou Bridge, the local MSA officials are now able to stop and inspect any passing vessels that they suspect of overloading.

On 22 November, the Yangtze MSA issued an urgent warning to all captains that their licences would be suspended or even revoked if their vessels became stranded because of overloading; they would also receive a fine.