Although the advances by Europeans in science and industry made them dangerous rivals to the empire, the Chinese continued to treat Europeans as just another type of barbarian. Confrontation occurred over the importation of opium from India into China. The British lacked commodities, apart from silver, to exchange for Chinese goods. Indian-grown opium reversed the trade balance in their favor, but the Chinese saw the trade as a threat to their social order. Silver left the country, and opium addiction became rampant. Government efforts to check the problem failed until the 1830s when an important official, Lin Zexu, came to end the trade at Canton and nearby. When he blockaded European trading areas and destroyed opium, the merchants demanded and received military intervention. The British invaded in 1839; the Chinese were defeated on sea and land and sued for peace. Another conflict ended similarly in the 1850s. The settlement after the first war awarded Hong Kong to the British and opened other ports to European trade and residence. By the 1890s, 90 ports were open and foreigners had gained long-term leases over ports and surrounding territory. Opium continued to pour into China. By mid-century, British officials managed China's foreign trade and customs system, and the court had to accept European ambassadors.
How did China's losses in the Opium Wars affect the rising dominance of European powers in East Asia?
From the looks of the post, it seems much of the answer is already, though indirectly, part of the preceding paragraph. To elucidate: the influx of opium among the Chinese meant that the market became saturated with a ...
The crucial role of opium in the trade relationship between China and European merchants is explained in brief.