Building with built-up area of 5,000 square metre and above are required to take environment clearance from the Union ministry of environment.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/chandigarh-exempt-big-buildings-environment-clearance
[2] http://admin.indiaenvironmentportal.org.in/category/author/vinod-kumar
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/economic-times-new-delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/punjab
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/chandigarh
[6] http://admin.indiaenvironmentportal.org.in/thesaurus/environment-clearance-ec
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/buildings
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ministry-environment-and-forests-moef
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy-efficiency
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment