NEW DELHI — As November surface wind speeds drop below 6 km/h and a shallow radiational temperature inversion caps the atmospheric mixing height across the National Capital Region at under 400 metres, the Commission for Air Quality Management (CAQM) has enforced stringent Graded Response Action Plan (GRAP) emergency countermeasures across Delhi, Noida, Gurugram, Faridabad, and Ghaziabad.
Atmospheric Inversion and Real-Time Source Apportionment
Data from Delhi’s real-time source apportionment supersites reveals that mid-November smog episodes are driven by a complex chemical cocktail: local vehicular nitrogen oxides ($ ext{NO}_x$) reacting with ammonia and sulphur dioxide to form secondary inorganic aerosols, compounded by transboundary agricultural residue plumes from the northwest Indo-Gangetic Plain.
IIT Kanpur Cloud Seeding Readiness and Meteorological Constraints
Environmental authorities have coordinated airspace clearances with the Directorate General of Civil Aviation (DGCA) for IIT Kanpur’s cloud-seeding research aircraft. However, meteorologists at the India Meteorological Department (IMD) caution that glaciogenic and hygroscopic flare dispersion is only effective when an approaching Western Disturbance provides nimbostratus cloud cover with liquid water content above threshold levels.
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