If you lived in any major city across the world on Thursday but somehow had to breathe Delhi's air, your city would declare an emergency. As Paris implements emergency measures to tackle poor air quality, here's a look at what Delhi looked like on days that other cities declared unsafe for its residents.
* On December 6, Paris took half cars with odd numbered plates off the streets as an emergency measure because of unacceptably high levels of air pollution. Its highest local AQI on that day? 158.
Delhi - 451
* On December 7, Paris took even numbered cars off the streets. AQI - 150
Delhi - 299
* March 6, 2016: Mexico City takes 40% of cars off roads, gives free access to public transport and makes industries cut emissions when AQI touches 203
Delhi - Over 200
* Dec 8, 2015 - China issues its first ever 'red alert', shutting schools, closing construction sites and taking half the cars off the road. AQI - 365
Delhi - 380
* Sep 25, 2015: Smoke from forest fires causes AQI in Singapore to go over 300, leading to schools being shut and outdoor events cancelled.
Delhi - 350
(All data based on World Air Quality data, and Index values are US EPA for comparability)