This might have something to do with it:China crude carrier...

This might have something to do with it:

China crude carrier capacity stretched: COSCO
Reuters

CHENGDU -- China's fleet of very large crude carriers (VLCCs) will soon surpass the country's domestic needs if an expansion plan proceeds as expected, an official with China's leading shipping firm said.

Concerned that its reliance on foreign carriers could be disrupted during times of political volatility including wars, Beijing has been aggressively promoting the construction of its own fleet in recent years.