It would take five years and cost $40 billion.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/russia-moots-mega-energy-pipeline-project-india
[2] http://admin.indiaenvironmentportal.org.in/category/author/suhasini-haidar
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/hindu-new-delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/russia
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/natural-gas
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy