The opium wars occurred because attempted to control or eliminate imports of opium by traders.

The opium wars occurred because China attempted to control or eliminate imports of opium by British traders.British East India Company paid Chinese their goods with opium from British India. Chinese users began to smoke the opium, usage and addiction increased and Chinese government wanted to stop opium trade with British.
First Opium War escalated in 1839 and last until 1842.