The world's largest "science exhibition on wheels", the Science Express themed on climate change this year, was on Friday flagged off by India's Science, Environment and Railway ministers here.The 16-coach AC Science Express Climate Action Special train, custom-built by the Indian Railways, will embark on a 205-day journey of over 19,000 km to cover 68 locations across India till September 8, 2017.The train is expected to attract 30 lakh visitors this year. It was jointly flagged off by Union Environment Minister Anil Madhav Dave, Science Minister Harsh Vardhan and Railway Minister Suresh Prabhu from the Safdarjung Railway Station in Delhi."The aim is to transform this vehicle into a peoples' movement and to motivate people to take individual actions and initiatives to fight climate change," Anil Madhav Dave said.Dave added that to tackle climate change everyone's role has to be determined and in future the train will reach 6.5 lakh villages.This is the ninth tour of the Science Express since 2007. It holds the record for the largest, longest running and most visited mobile science exhibition with six entries in Limca Book of Records.The train was dedicated to the climate change for the second consecutive year.The Science Express will be open for public viewing at Delhi Cantonment Railway Station on February 18-19.Railway Minister Suresh Prabhu described climate change as a major global issue and pointed out that India played a key role in initiating climate action plan as part of solutions."Climate Change is a big threat for the mankind, we can tackle through collaborative efforts," Prabhu told reporters after flagging off the Science Express Climate Action Special train here. Minister of Science Harsh Vardhan said that the role of school students is most critical in making the Science Express a peoples' movement. "Over 1.5 crore visitors and students from 33,801 schools have visited the Science Express till now," Harsh Vardhan pointed out.