Tens of thousands of pro-democracy demonstrators have gathered in Hong Kong’s Central financial district to protest Beijing’s broken promise. When Britain returned control of the city to the People’s Republic on July 1, 1997, the mainland government had pledged to abide by a system of “one country, two systems” that would guarantee many of the special rights that Hong Kong had enjoyed under British rule. Part of that pledge included the right to choose its own democratically elected leadership by 2017.

Yet Beijing’s Chinese Communist Party appears to be reneging on that deal. In August, the CCP issued a white paper announcing that candidates for Hong Kong’s 2017 chief executive election would have to be approved by Beijing, giving mainland authorities the ability to weed out the candidates it doesn’t like. As peaceful protesters took to the streets over the weekend, the Beijing-backed Hong Kong government has responded with pepper spray and tear gas. The demonstrators raised umbrellas—to shield themselves from the chemicals. If Beijing doesn’t tread carefully, the “umbrella revolution” may only grow stronger.