Cloud Seeding and Air Pollution Concerns

Summary of Cloud Seeding and Air Pollution in Delhi

Definition and Process of Cloud Seeding

1. Cloud Seeding: A weather modification technique where substances like silver iodide or sodium chloride are introduced into specific types of clouds to induce rainfall.
   • Mechanism: These substances act as nuclei around which moisture condenses to form rain.
   • Effective Conditions: Seeding is effective primarily in hygroscopic or warm-rain clouds, which contain abundant liquid water.

Limitations of Cloud Seeding

1. Cloud Availability: Hygroscopic clouds are rare and form under specific atmospheric conditions.
   • Occurrence Probability: Approximately 51% during pre-monsoon/post-monsoon months; drops to 5-10% in winter (peak air pollution period).
2. Success Rate: Global success rate of cloud seeding is roughly 50% under ideal conditions; however, the likelihood of these conditions coinciding with high AQI events is significantly lower.

Recent Cloud Seeding Experiment in Delhi

1. Experiment Date: Conducted on October 28, 2025.
2. Outcome Claims: Proponents reported an improvement from "Very Poor" to "Poor" AQI in certain areas post-experiment.
3. Statistics: AQI improvements do not address the persistent high PM2.5 concentrations above national standards.

Health and Environmental Impacts

1. Health Risks: Initial exposure to PM2.5 is most harmful; increased rainfall under specific conditions can lead to secondary aerosol formation, worsening air quality.
2. Systemic Issues: Emissions rapidly accumulate, and temporary solutions like cloud seeding offer short-lived relief.

Broader Context and Recommendations

1. Underlying Factors: The discourse surrounding air pollution often focuses on transitory causes such as crop residue burning and festival fireworks, neglecting systemic drivers.
   • Suggested Approach: Emphasize an airshed strategy to consider the movement of pollutants across administrative boundaries.
2. Long-term Mitigation: Solutions must target year-round persistent pollution sources, such as vehicular emissions (contributing over 40% to Delhi's PM2.5).
   • Accelerate transition from fossil fuels and promote electric vehicle adoption.

Policy and Institutional Framework

1. National Resource Framework of India (NARFI): Advocated for a holistic approach to air quality management, promoting scientific assessments and innovative solutions.
2. Government’s Role: Enhanced coordination and policy mechanisms are essential for a comprehensive air quality strategy.

Conclusion

• Urgency for Action: Air pollution is a major public health crisis that transcends seasonal and administrative boundaries, necessitating serious, integrated, and sustained efforts across sectors to improve ambient air quality in Delhi and beyond.