The Mong Kok acid attacks 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 . 130 people were injured in these attacks
Mong Kok acid attacks
Hong Kong acid attacks
Acid throwing