Wheat is harvested in this belt during the last week of April.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/despite-challans-and-subsidies-farmers-stubble-burning-season-returns-punjab-haryana
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/haryana
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/punjab
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/crops
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi-pollution-control-committee-dpcc
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/centre-science-and-environment-cse