HONG KONG (AP) — Colin Wong has come to know the sting of pepper spray well.

After more than a month of demonstrations in Hong Kong's sweltering heat, memories of the burning sensation are a constant reminder of what protesters call an excessive use of force by police. Each time he felt the now-familiar sting, Wong was more determined to not back down.

What began as a protest against an extradition bill has ballooned into a fundamental challenge to the way Hong Kong is governed — and the role of the Chinese government in the city's affairs. "Hong Kong is not China" has become a refrain of the movement in what is a Chinese territory, but with its own laws and a separate legal system under a "one country, two systems" framework.