Hart Energy Publishing's International Fuel Quality Center recently released a ranking of the top 100 countries based on sulfur limits on on-road diesel. Sweden was found to be at the top of the ranking, followed by Germany and Japan, being sole position-holders of second and third place, respectively.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/top-100-countries-ranked-low-sulphur-road-diesel-regulations
[2] http://admin.indiaenvironmentportal.org.in/category/author/louise-poirier
[3] http://admin.indiaenvironmentportal.org.in/category/journal/fuel
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution-control
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/diesel
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ultra-low-sulphur-diesel
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/transport
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/japan
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/germany
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/sweden
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/statistics