The India Meteorological Department defines heat waves under two categories. The first category includes places where the normal maximum temperature is more than 40
Links:
[1] http://admin.indiaenvironmentportal.org.in/feature-article/definition-degrees
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/down-earth
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-change
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/heat-waves
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/indian-meteorological-department-imd
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india