As part of the pilot project, a fleet of CNG buses would be introduced in Kochi and later it would be expanded to cities like Thiruvananthapuram and Kozhikode.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/kerala-shift-cng-powered-vehicles-introduce-1000-buses
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kerala
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[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/cng-buses
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution-control
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/public-transport