The IFQC has ranked the top 100 countries based on benzene limits in gasoline.
Links:
[1] http://admin.indiaenvironmentportal.org.in/reports-documents/international-gasoline-rankings-top-100-benzene
[2] http://admin.indiaenvironmentportal.org.in/category/publisher/international-fuel-quality-center
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/benzene
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/fuel-quality
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/petrol
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/fuel-standards
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/global