Total emissions from motor vehicles fell 12% from 2012 to 2016, according to the Office for National Statistics.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/uk-air-pollutants-continue-decline
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/bbc-uk
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/united-kingdom-uk
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/oxides-nitrogen-nox
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/cars
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/nitrogen-dioxide
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-monitoring