The Mong Kok acid attacks (旺角高空投擲腐蝕性液體傷人案) were incidents in 2008, 2009, and 2010 where plastic bottles filled with corrosive liquid (drain cleaner) were thrown onto shoppers on Sai Yeung Choi Street South, Hong Kong, a pedestrian street and popular shopping area. A reward, originally HK$100,000, for information about the perpetrator or perpetrators, was raised to HK$300,000 following the second incident, and cameras were to be installed in the area following the December incident. The third incident occurred the very day the cameras were turned on. The fifth incident happened after Hong Kong government announced its new strategies against the incident. 13 December 2008 incident The first incident occurred on 13 December at 5:15pm near the intersection of Sai Yeung Choi Street South and Shantung Street. Two bottles of an unspecified corrosive liquid were hurled into the crowd, possibly from the 12th floor of the Yuen King Building, onto a popular pedestrianised street area below where many were doing Christmas shopping. The bottles hit the ground and exploded, splashing 46 people with corrosive fluids that burned through clothes and skin. People took refuge in nearby shops as water was poured onto the spilled acid to dilute it. All injuries were minor and the injured were all released from the hospital by the next day. Two days after the attack, Hong Kong Chief Executive Donald Tsang personally came to examine the area. Investigation of the attack left the intersection closed for approximately two hours on 16 December as police re-enacted the incident. Investigators threw bottles of chalk powder from several vantage points to gauge the exact point they might have been thrown from. Water was also poured on the ground to provide a better examination of splash and flow patterns. Door to door interviews were also performed. That same day, a reward of HK$100,000 (approx. US$12,800) was offered for any information about the attack, officially classified as "throwing corrosive fluid with intent to do grievous bodily harm," a formula usually shortened to "throwing corrosive fluid with intent". The maximum punishment for this crime is life imprisonment. An individual claiming to be a Triad member later claimed online to have committed the attack, but was never traced. A month after the attack, Yau Tsim Mong District Council voted to install four CCTV cameras in various areas with the specific aim of deterring litter-hurling in general (throwing objects from buildings is a problem in