Yang is one of many innocents attacked by rampaging rioters during Hong Kong's months-long social unrest. On the day Yang was attacked, a 57-year-old local man was doused with a flammable liquid and set on fire after a dispute with rioters over political views in the Ma On Shan area.

A Japanese man who came to Hong Kong for business was also battered by rioters that day, as confirmed by Japanese authorities the following day.

Until now, Hong Kong has recorded at least 45 cases of people being beaten over political positions, with one death, according to the city's police watchdog, Independent Police Complaints Council (IPCC).

The IPCC recently released a report on the social unrest, indicating that initially peaceful demonstrations turned into violent protests.

The report found that violence occurred more frequently after marches and demonstrations, with escalation and early signs of terrorism. There had been widespread destruction of public and private property, causing long-term damage to the economy.

Yang said he has applied for the assessment of his injuries, hoping that the Hong Kong police could arrest the mobs and he might receive compensation one day. "But they were all masked, so it's difficult to identify them," he said in a hopeless tone.

Unlike other victims, Yang was captured in an award-winning picture. It shared the great misfortune and shone a spotlight on a dark chapter of Hong Kong's rule of law as rioters went on a rampage.

Regret over that trip spilled over again. "It should have had nothing to do with me. What if I hadn't gone to Hong Kong? What if I hadn't met those mobs?"

(Video reporters: Qiu Bo, Liang Jiajun; Video editor: Luo Hui)