Verified Answer :

The answer is Opium War that was fought between China and
Great Britain.  This was due to the
growing problem caused by the Opium trade by the British.  This alarmed the Chinese and destroyed some
of the opium being sold by the British.
This led to war and China was defeated.
The Treaty of Nanking where the British acquired businesses from China
without any commitments.

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British merchants selling illegal opium in China

is the exact wording of the answer as of Apex 2018