Overview
- On Thursday, November 12, Delhi’s city‑average AQI stayed in the very poor range at roughly 319–326 while dozens of monitors reported readings above 300 and several sites including IIT Delhi registered severe levels above 400.
- Official CPCB figures use reference‑grade BAM/TEOM analysers with 24‑hour averages and a capped scale, while private dashboards use optical sensors and US/EPA scaling that show instantaneous spikes up to about 600, creating widely different headline numbers.
- The CPCB says some older reference analysers briefly stopped publishing during peak hours because automated validation discarded out‑of‑range readings when raw concentrations exceeded instrument calibration limits.
- Multiple analyses and modelling point to heavy local transport emissions as the single largest, persistent source of PM2.5, with Diwali firecrackers and seasonal farm‑fires supplying short‑term extra loads that meteorology has trapped over the city.
- Emergency GRAP measures (Stage II/III) remain in force, public health warnings are in effect and the poor air raises near‑term risks for children, the elderly and people with lung or heart conditions while political disputes and enforcement gaps shape the response.