Cloud Seeding Trials Begin in Delhi

Summary Notes: Cloud Seeding Trial in Delhi

Event Overview:

• A cloud seeding trial was conducted in Delhi on October 28, using a Cessna 206H aircraft.
• The aircraft operated from IIT-Kanpur and covered regions such as Burari, Mayur Vihar, and North Karol Bagh.
• This trial is noted as potentially the first significant attempt in India to use cloud seeding scientifically to mitigate air pollution.

Technical Aspects of Cloud Seeding:

• Definition: A technique to modify clouds with 'seed' particles for increasing rainfall (IITM document, 2024).
• Process: Utilizes particles that promote condensation and form raindrops (cloud condensation nuclei - CCNs, and ice nuclei).
• Execution: Involves injecting clouds with salts (e.g., silver iodide, potassium iodide, sodium chloride) via aerial flares—each weighing 2-2.5 kg.

Conditions for Cloud Seeding:

• Requires cloud cover of specific types, adequate humidity (15-20%), and the right conditions for droplets to coalesce effectively.
• Influenced by western disturbances, which bring non-monsoonal rainfall to northwest India.

Implementation Details:

• Duration: Each flare took approximately 2-2.5 minutes for deployment.
• Expectations: Light rains were anticipated within a few hours post-experiment if conditions were favorable.

Historical Context and Efficacy:

• First attempted in the 1940s globally, cloud seeding in India has primarily focused on alleviating drought rather than addressing air quality directly.
• Past IITM studies indicated a potential 24% increase in rainfall in favorable conditions (Murthy et al., 2000).
• Rain is expected to wash away pollutants (PM 2.5, PM 10), addressing temporary air quality issues.

Concerns and Challenges:

• Efficacy doubts remain, given that the strategy focuses on symptomatic treatment rather than addressing root causes such as vehicular emissions, industrial pollution, stubble burning, and dust.
• Experts stress the importance of comprehensive measures to tackle air pollution effectively instead of relying solely on artificial rain.

Policy and Government Initiatives:

• This trial aligns with broader environmental strategies and policies aimed at pollution mitigation in urban areas.
• The Ministry of Earth Sciences plays a crucial role in overseeing such experimental approaches.

Conclusion:

The cloud seeding trial in Delhi represents a significant experimental approach to combat air pollution, leveraging meteorological science. However, while promising in theory, its long-term effectiveness and the need for sustainable pollution control measures remain points of critical discussion.