According to scientists, the PM 2.5 concentration in Delhi on Sunday was 273 micrograms per cubic metre.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/delhi-pollution-level-high-despite-strong-wind
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/indian-express-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pm-25
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/central-pollution-control-board-cpcb
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/air-quality-index-aqi