The Zero Bus looks like a regular Mercedes Citaro bus except for the nine hydrogen tanks laid discreetly across its roof. That is the telltale sign that the Zero is in fact different :Tucked inside
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/europes-green-cars-may-be-humming-sooner-expected
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/business-week-new-york
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution