Passive solar heating of houses is a clean technology which was made mandatory in the government/semi-government sector in 1994 in the Western Himalaya state of Himachal Pradesh. HP is the first state in India to take such a policy decision for promoting energy efficiency in buildings. A Solar House Action Plan was formulated and is being implemented effectively in the state.
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/strategy-passive-solar-heating-buildings-cold-regions-india
[2] http://admin.indiaenvironmentportal.org.in/category/author/s-s-chandel
[3] http://admin.indiaenvironmentportal.org.in/category/journal/akshay-urja
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy-policy
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy-efficiency
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/solar-energy
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/solar-thermal-power
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/green-buildings
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/energy
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/himachal-pradesh
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/lahul-spiti
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/shimla-d