According to World Health Organization, India has an estimated 15-20 million asthmatics.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/world-asthma-day-tips-fight-breathlessness
[2] http://admin.indiaenvironmentportal.org.in/category/author/kalpana-sharma
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-new-delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/asthma
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/who
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/health-effects
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-standards
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pm-25
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/india
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/children
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/child-health