An earlier SC order and a recent High Court order make such clearance mandatory
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/50-quarries-sans-clearance-face-closure
[2] http://admin.indiaenvironmentportal.org.in/category/author/radhakrishnan-kuttoor
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/hindu-thiruvananthapuram
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/kerala
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mining
[6] http://admin.indiaenvironmentportal.org.in/thesaurus/environment-clearance-ec
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/minor-minerals
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment-impact-assessment-eia
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/high-court
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mines-act-1957