Missing pollution data in Delhi hides true Deepavali air quality levels

UPDATE - follow-up to At peak of air pollution on Deepavali night, data goes missing at several govt monitoring stations in Delhi: Air quality data vanished from multiple government monitoring stations in Delhi at the peak of Deepavali night pollution. DPCC and CPCB websites showed blank readings for several hours across areas like Anand Vihar, Patparganj, and Bawana.

Missing Data Impact

Centre for Research on Energy and Clean Air analyst Manoj Kumar stated that 227 hourly PM2.5 observations were missing across 59 CPCB stations between midnight on November 8 and 5 a.m. on November 9. Only 14 stations reported complete data. Mr. Kumar explained that missing hourly PM2.5 data artificially lowers the Air Quality Index, showing better air quality than what actually exists.

Extreme Pollution Levels

Before data went blank, Patparganj recorded a PM2.5 level of 2,597 micrograms per cubic metre at 1 a.m. on Monday, which is 173 times the WHO limit of 15 micrograms. Anand Vihar recorded 1,396 micrograms per cubic metre at 3 a.m., or 93 times the limit. Meanwhile, the CPCB public portal capped PM2.5 readings at 1,000 micrograms per cubic metre, showing more gaps than the DPCC site. A similar data disappearance happened last year during Deepavali.

Political Reactions

Delhi Labour Minister Kapil Mishra told the media the government would look into the issue within an hour. Both the AAP and the Congress attacked the government over the missing numbers, with AAP calling it data fraud. In response, Mr. Mishra alleged a conspiracy by AAP-governed Punjab to set stubble on fire on Sunday evening.

Context

PM2.5 refers to fine inhalable particles that enter the lungs and bloodstream to cause serious health issues. When pollution monitoring portals lose live feeds or cap high readings, residents lose access to accurate safety warnings during critical public health emergencies.