Germany has successfully tested the world's first helicopter which is noiseless and emission-free, thus dubbed as the 'green helicopter'.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/worlds-first-green-helicopter-tested-germany
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/zee-news
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/germany
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/zero-emissions-vehicles
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/noise-pollution
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/advanced-vehicle-technology