Supreme Court order dated 26/03/2001 in the case of M. C. Mehta Vs Union of India and Ors on vehicular pollution in Delhi.
Links:
[1] http://admin.indiaenvironmentportal.org.in/reports-documents/supreme-court-order-dated-26032001-case-m-c-mehta-vs-union-india-and-ors-vehicular
[2] http://admin.indiaenvironmentportal.org.in/category/publisher/supreme-court-india
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/cng-buses
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/supreme-court
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/urban-air-quality
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/private-sector
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/public-transport