Description

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Context

In a proactive move to combat Delhi winter air pollution crisis Delhi Environment Minister has initiated discussions on artificial rain through cloud seeding engaging multiple central & scientific agencies to explore feasibility of trial operations.

Key Highlights

Delhi Environment Minister initiated a high level meeting ahead of Delhi winter pollution season to explore artificial rain through cloud seeding as a short term solution to air pollution.

The meeting involved multiple key agenciesCentral Pollution Control Board (CPCB), Delhi Pollution Control Committee (DPCC), Ministry of Defence, Home Affairs, Environment, Indian Institute of Tropical Meteorology (IITM), IIT-Kanpur (technical experts on cloud seeding), Directorate General of Civil Aviation (DGCA) & Airport Authority of India

During winters western disturbances bring rain to Delhi naturally washing away pollutants. Cloud seeding attempts to mimic this natural phenomenon using aircraft & salt based mixtures to induce rain & clean air.

Cloud Seeding is a scientific process involving dispersal of substances (typically silver iodide, potassium iodide or sodium chloride) into clouds.

These act as nuclei for water droplets to condense around increasing likelihood of rainfall.

IIT-Kanpur conducted successful pilot trials in 2023 during monsoon with favorable conditions. Earlier trials in April to May 2018 resulted in 5 out of 6 attempts producing rain though they covered limited areas.

No cloud seeding trials have been conducted in Delhi winter months when clouds are sparse & humidity is low.

Weather dependency is high requires ideal cloud moisture & atmospheric conditions.

A static system for natural ionisation based artificial rain was also presented as a potential low-cost, long term alternative to aerial cloud seeding.

Dust Pollution Mitigation (14-point Plan Reviewed)

Dust from construction sites contributes to nearly 30% of Delhi’s winter air pollution.

Action items include Use of anti-smog guns, Covering sites with tarpaulin or green nets, Regular cleaning of vehicles carrying construction material & Proper debris storage/disposal

Types of Cloud Seeding Techniques

Type	Description	Common Agents Used	Application Areas
Static Seeding	Involves dispersing agents to stimulate ice crystal formation in cold clouds.	Silver iodide, Potassium iodide	Snow enhancement, winter precipitation
Dynamic Seeding	Enhances vertical air currents to increase cloud productivity.	Silver iodide, Urea, Dry ice	Large-scale rainmaking
Hygroscopic Seeding	Focuses on warm clouds by using salts to form raindrop nuclei.	Sodium chloride, Calcium chloride	Tropical climates, drought relief
Ground-Based Seeding	Agents released from ground generators or cannons directed at clouds.	Silver iodide (via flares), salt aerosols	Remote locations, low-altitude clouds
Aircraft-Based Seeding	Aircraft fly into or above clouds, dispersing agents directly.	Silver iodide, dry ice, hygroscopic salts	Urban air pollution control

Global Examples of Cloud Seeding Projects

Country	Project Name / Location	Objective	Outcome / Remarks
UAE	UAE Cloud Seeding Program	Drought mitigation, water security	Over 1,000 missions per year; some success reported
China	Tianjin, Beijing, Qinghai Projects	Olympic air clearing, drought response	Claimed largest cloud seeding program in world
USA	Colorado, Nevada, North Dakota	Snowpack augmentation	Long-standing programs in Western US states
India	Maharashtra (2015), Karnataka (2003)	Drought relief	Mixed results; success dependent on weather conditions
Thailand	Royal Rainmaking Project	Agricultural enhancement	Continuously active since 1950s

Scientific & Technical Requirements for Cloud Seeding

Requirement	Details
Cloud Type	Typically cumulus or stratocumulus clouds with sufficient vertical depth
Cloud Base Temperature	Between -5°C & -20°C for effective ice nucleation (cold clouds)
Relative Humidity	Preferably above 80% for droplet formation
Wind Speed	Moderate winds required to disperse seeding agents evenly
Aircraft/Launch Platform	Must be capable of flying through or above target clouds
Meteorological Data	Continuous radar, satellite & ground data for real-time monitoring

Environmental & Ethical Considerations

Aspect	Details / Concerns
Ecological Impact	Long-term seeding may alter local climate & precipitation patterns
Legal Issues	Transboundary weather modification may lead to international disputes
Health Concerns	Use of silver iodide in large quantities may raise concerns over toxicity
Cost Effectiveness	Cloud seeding is expensive & success is unpredictable
Ethical Dilemmas	Who controls rainfall? Could one region benefit at another’s expense?

India-Specific Cloud Seeding Initiatives

State	Year	Purpose	Agency / Partner	Result
Maharashtra	2015	Drought mitigation in Marathwada	MIT Pune, private contractors	Limited success; heavily dependent on clouds
Karnataka	2003	Rainfall enhancement	ISRO collaboration	Partial results; discontinued due to cost
Andhra Pradesh	2004 to 09	Agricultural water security	National Remote Sensing Agency	Variable outcomes
Tamil Nadu	2004	Rain increase in dry districts	International firms	Expensive; not repeated on same scale

Artificial Rain

Aspect	Details
Definition	Artificial rain refers to human induced precipitation typically by modifying cloud microphysics to trigger rainfall using cloud seeding or other methods.
Primary Technology Used	Cloud seeding is most common technique but other emerging methods include ionization, laser pulse technology & nanotechnology based cloud manipulation.
Non-Seeding Methods	Electrostatic ionization Charges atmospheric particles to create cloud condensation nuclei. Laser pulses Create plasma channels to induce condensation.
Key Pre-conditions	Presence of moisture laden clouds Adequate atmospheric instability Favorable temperature & humidity levels
Major Applications	Combating urban air pollution (e.g. Delhi) Drought mitigation in agriculture Water resource management Snowpack augmentation
Global Examples	China Weather modification for drought & Olympic air clearing Thailand Royal Rain Project UAE Uses both seeding & ionization
Challenges	High cost & logistics Unpredictable outcomes Requires coordination with aviation & meteorology departments Not a long-term climate solution
Regulatory Oversight	In India artificial rain experiments must be cleared by DGCA (aviation), Ministry of Defence, IMD & MoEFCC for airspace & environmental safety.
Ethical & Environmental Risks	May affect downwind regions rainfall No universal laws on inter-regional weather rights Potential ecological impact of prolonged artificial rainfall

For more such articles, please refer to IAS GYAN

Sources:

INDIAN EXPRESS

PRACTICE QUESTION

Q.Discuss potential & limitations of artificial rainmaking technologies like cloud seeding as a solution to urban air pollution in India. How should India balance scientific innovation with environmental ethics in such interventions?