CRC/C/CHN/CO/3-4 (b) The widespread involvement of children in hazardous work and the worst forms of child labour, especially in the mining, manufacturing and brick industries; and inadequate protection of children aged 16–18 against hazardous work. 86. The Committee urges the State party to, as a matter of priority, end the use of the RTL and “work study schools” programmes and that it: (a) Gather data on child labour, incidences of hazardous child labour and working conditions, disaggregated by age, sex, geographical location and socioeconomic background, and make such data publicly available and use it to develop effective measures to prevent and eliminate all forms of child labour; (b) Identify hazardous work and worst forms of labour carried out by children and prohibit employment of children aged 16–18 in arduous work; (c) Ensure, with respect to children above the age of 16 involved in labour, that their involvement is based on genuine free choice and subject to adequate safeguards based on the Convention and international standards, including through the application of sanctions against individuals involved in forced recruitment; (d) Consider ratifying International Labour Organization Convention No. 189 (2011) concerning Decent Work for Domestic Workers. Sale, trafficking and abduction, including follow-up to the Optional Protocol on the sale of children, child prostitution and child pornography 87. The Committee regrets that the State party has not sufficiently implemented the Committee’s recommendations of 2005 under the Optional Protocol on the sale of children, child prostitution and child pornography (CRC/C/OPSC/CHN/CO/1). It is further concerned at the increased prevalence of child trafficking and exploitation in mainland China and Macao, China, especially for the purpose of labour and sexual exploitation. It is also concerned that child sex tourism remains a serious problem in Macao, China and that alleged complicity of government officials in offences related to trafficking and sexual exploitation has led to impunity for such crimes. 88. The Committee recalls its previous recommendations and urges the State party to take the necessary legislative measures to harmonize the 1997 Penal Code with the provisions of the Optional Protocol on the sale of children, child prostitution and child pornography, and in particular: (a) Ensure that all the offences referred to in article 3, paragraph 1, of the Optional Protocol are fully covered under the Penal Code, whether such offences are committed domestically or transnationally or on an individual or organized basis, paying particular attention to the sale and trafficking of children for the purpose of adoption; (b) Establish extraterritorial jurisdiction over the offences referred to in article 3, paragraph 1, in conformity with article 4, paragraph 2, of the Optional Protocol; and abolish the requirement of double criminality for prosecution on the mainland of offences committed abroad; (c) Consider the Optional Protocol as a legal basis for extradition in respect of such offences, in conformity with article 4, paragraph 2, of the Optional Protocol. 89. The Committee further recommends that the State party: (a) Undertake research on the root causes and extent of the commercial sexual exploitation of children, child sex tourism and sale of children, child prostitution and child pornography, to identify children at risk, assess the extent of 20