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Air quality

Cloud Seeding Experiment in Delhi Raises Methodological Concerns

Strategic Insights

— 2 min read

A report from IIT Kanpur, cited by Delhi environment minister Manjinder Singh Sirsa, claims that the cloud seeding experiment in Delhi was somewhat successful in improving air quality and rainfall. However, a closer examination of the data reveals methodological failures that render the findings unreliable. The report cites rainfall data from Windy.com, a website that displays modeled estimates rather than measured rainfall, and air quality data that is reported without specifying units, making it impossible to determine whether the concentrations are reported or index values. Additionally, the report fails to specify the averaging period for its measurements, the timing of the measurements, and the location of the monitoring stations, which raises concerns about the comparability and reliability of the data.

Key Takeaways:

  • The IIT Kanpur report cites rainfall data from Windy.com, a website that displays modeled estimates rather than measured rainfall.
  • The report cites air quality data that is reported without specifying units, making it impossible to determine whether the concentrations are reported or index values.
  • The report fails to specify the averaging period for its measurements, the timing of the measurements, and the location of the monitoring stations.
  • The experiment was conducted in two sorties, with seeding taking place roughly between 2 PM and 5 PM, coinciding with the natural daily improvement in air quality in the afternoon.
  • The report claims that the PM 2.5 and PM 10 concentrations reduced after cloud seeding, but it is impossible to determine how long the improvement lasted or whether the measurements are even comparable.
  • The IIT Kanpur director stated that his team set up 15 stations in different parts of Delhi, but did not provide details about their type and location.
  • At least one of the locations cited, Burari Crossing, is covered by an India Meteorological Department air quality station, which shows that air quality consistently improves between noon and 6pm, then deteriorates in the late evening and night.

Statistics:

  • The PM 2.5 concentrations reduced from 221, 230, and 229 to 207, 206, and 203 at Mayur Vihar, Carol (Karol) Bagh, and Burari, respectively, after cloud seeding.
  • The PM 10 concentrations reduced from 207, 206, 209 to 177, 163, 177 at Mayur Vihar, Carol Bagh, and Burari, respectively, after cloud seeding.
  • The experiment was conducted over a period of two sorties, with seeding taking place roughly between 2 PM and 5 PM.
  • The report cited air quality data from 20 locations, but only three locations were mentioned: Mayur Vihar, Carol (Karol) Bagh, and Burari.

Sources:

  • IIT Kanpur report (no date provided)
  • Hindustan Times (October 29, 2022)
  • Central Pollution Control Board (CPCB) (no date provided)
  • India Meteorological Department (no date provided)
  • Windy.com (no date provided)

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