E/C.12/COL/CO/6 and adolescents, particularly indigenous, Afro-Colombian and internally displaced children and adolescents; (b) Intensify its efforts to ensure that access to preschool education is extended to all children, especially those belonging to the most disadvantaged and marginalized groups; (c) Take appropriate measures to reduce dropout and repetition rates in secondary education, particularly among indigenous and Afro-Colombian children, including by strengthening the bilingual intercultural education system; (d) Intensify its efforts to ensure the availability of free education and to do away with the exceptions to this principle set out in Decree No. 4807 of 2011; (e) Take all necessary measures to enhance the quality of teaching by increasing the number of qualified teachers, ensuring that they receive adequate remuneration and benefits, and to improve educational infrastructure and teaching materials; (f) Intensify its efforts to guarantee children and adolescents with disabilities access to inclusive education. Cultural rights 65. The Committee notes with concern that the measures adopted to ensure respect for the cultural diversity of indigenous and Afro-Colombian peoples and to foster the use of indigenous languages remain limited. Furthermore, the Committee is concerned that not enough is being done to promote indigenous and Afro-Colombian traditions and culture and the use of their languages (art. 15). 66. The Committee recommends that the State party adopt the necessary measures to provide greater protection for cultural rights and to promote greater respect for cultural diversity. The Committee further recommends that the State party create an enabling environment in which indigenous peoples and Afro-Colombian populations may preserve, develop, express and disseminate their identity, history, culture, languages, traditions and customs. Participation in scientific activities 67. The Committee regrets that the participation of women in the scientific sphere in the State party remains low and that there is little information on the practical measures adopted to remedy that situation (art. 15). 68. The Committee recommends that the State party adopt the necessary measures to facilitate and ensure women’s access to and participation in the scientific sphere and requests it to include in its next periodic report information on the results yielded by those measures. D. Other recommendations 69. The Committee encourages the State party to ratify the Optional Protocol to the International Covenant on Economic, Social and Cultural Rights. 70. The Committee encourages the State party to ratify the Optional Protocol to the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment; the Optional Protocol to the Convention on the Rights of Persons with Disabilities; and the Optional Protocol to the Convention on the Rights of the Child on a communications procedure. 71. The Committee recommends that the State party take fully into account its obligations under the Covenant and ensure the full enjoyment of the rights enshrined therein in the implementation of the 2030 Agenda for Sustainable Development at the national level, with international assistance and cooperation when needed. Achievement of the Sustainable Development Goals would be significantly facilitated GE.17-18290 11