The Treaty stated that all custom duties must be negotiated with other countries. It therefore took away China's control of its own customs. Furthermore, the import duties were lowered from 65% to 5%, this effectively shattered China's home industries. The Nanjing Treaty abolished the system of Gong Hang. This allowed British merchants free trade in China.
The Treaty exempted British nationals from Chinese law, thus permitting the operation of extraterritorial law on Chinese soil. Furthermore, any Chinese who either dealt with the British, or lived with them or were employed by them were also exempted from Chinese law. This made foreign concessions a haven for Chinese criminals. To Chinese officials, this clause also gave foreign invaders the legal right to setup and protect their spy and criminal networks.