Cloud Seeding Trial to Combat Delhi Air Pollution

Delhi’s government launched its first cloud seeding trial in October 2025 to tackle severe air pollution. The initiative, in partnership with IIT Kanpur, aims to induce artificial rain to wash pollutants from the atmosphere. This marks India’s first operational cloud seeding attempt in the capital. The experiment marks both the promise and limitations of weather modification as a tool for environmental management.

Cloud Seeding Technology and Its Mechanism

Cloud seeding involves dispersing microscopic particles like silver iodide into clouds. These particles act as nuclei for moisture condensation, potentially increasing rainfall. Developed in the 1940s, the technique requires suitable cloud conditions. Without adequate humidity and cloud depth, seeding has little effect. Delhi’s dry late-October atmosphere posed a challenge, with humidity levels too low for effective rain formation during the trial.

Global Experience with Cloud Seeding

Internationally, cloud seeding has yielded mixed results. China and Thailand have reported modest success in enhancing rainfall. However, controlled trials in Israel and the United States found no increase in precipitation. Cloud seeding remains a probabilistic method, dependent on natural meteorological factors rather than a guaranteed solution.

Application for Pollution Control in Delhi

Delhi’s cloud seeding aims not at water augmentation but pollution reduction. Rainfall can temporarily lower particulate matter (PM2.5) by washing pollutants from the air. Yet, natural rains provide only brief relief as emissions quickly restore pollution levels. Artificial rain offers a similar short-term effect without addressing root causes like vehicle emissions, crop burning, and dust.

Environmental and Ethical Considerations

The use of silver iodide raises concerns about chemical accumulation in soil and water if cloud seeding is repeated frequently. Long-term environmental monitoring is crucial. Ethical questions also arise about altering weather patterns, such as the risk of depriving neighbouring areas of rainfall, known as cloud stealing. Transparency and public trust are vital in managing these concerns.

Policy and Regulatory Context in India

India lacks a comprehensive national policy on weather modification. Some states have experimented with cloud seeding for drought relief, but there are no standardised safety or environmental guidelines. The Delhi pilot puts stress on the need for the Ministry of Earth Sciences and the India Meteorological Department to develop a regulatory framework covering operational protocols, chemical use, and impact assessments.

Challenges and Future Directions

Cloud seeding is a politically visible but scientifically uncertain measure. It risks diverting focus from systemic pollution causes such as crop burning, vehicular emissions, and construction dust. Experts advocate prioritising structural reforms like emission controls, cleaner transport, and residue management. The ₹3.21 crore Delhi project is a scientific pilot meant to generate data rather than a definitive solution.

Operational Details of the Delhi Trial

The Delhi government and IIT Kanpur signed an MoU in September 2025 for five cloud seeding sorties during winter. The first flight on 28 October spread silver iodide over Burari and Karol Bagh. The experiment will be closely monitored for effects on rainfall and air quality. Honest communication about its limitations is essential to avoid unrealistic expectations.

Questions for UPSC:

1. Critically discuss the effectiveness and limitations of cloud seeding as a weather modification technique with examples from global practices.
2. Examine the environmental and ethical implications of artificial weather interventions like cloud seeding in the context of sustainable development.
3. Discuss in the light of India’s air pollution crisis, how structural reforms in transport and agriculture can complement technological interventions for pollution control.
4. Analyse the role of regulatory frameworks in managing emerging environmental technologies and their significance in ensuring public trust and ecological safety.

Answer Hints:

1. Critically discuss the effectiveness and limitations of cloud seeding as a weather modification technique with examples from global practices.

1. Cloud seeding enhances rainfall by dispersing particles like silver iodide to induce moisture condensation.
2. Its success depends entirely on suitable cloud conditions—adequate humidity and cloud depth are essential.
3. Global results are mixed – China and Thailand report modest success; Israel and the US found no statistically rainfall increase.
4. It is a probabilistic, not guaranteed, method—cannot create clouds, only augment existing ones.
5. In Delhi, dry atmospheric conditions limit its effectiveness, as seen in the low humidity during the 2025 trial.
6. Overall, cloud seeding is an experimental tool with uncertain outcomes, requiring rigorous scientific evaluation.

2. Examine the environmental and ethical implications of artificial weather interventions like cloud seeding in the context of sustainable development.

1. Repeated use of silver iodide may cause chemical accumulation in soil and water, necessitating long-term monitoring.
2. Potential ecological impacts include disturbance of natural weather patterns and unknown effects on local ecosystems.
3. Ethical concerns arise over cloud stealing, where induced rainfall in one area might reduce precipitation in neighboring regions.
4. Transparency in objectives, methods, and monitoring is crucial to maintain public trust and accountability.
5. Lack of comprehensive regulatory frameworks in India marks governance gaps in managing such technologies sustainably.
6. Artificial interventions should align with sustainable development goals, avoiding quick fixes that ignore root causes.

3. Discuss in the light of India’s air pollution crisis, how structural reforms in transport and agriculture can complement technological interventions for pollution control.

1. Major pollution sources include vehicular emissions, crop-residue burning, construction dust, and thermal power plants.
2. Technological fixes like cloud seeding offer only temporary relief without addressing these systemic causes.
3. Structural reforms – enforcing stricter vehicle emission norms and expanding electric public transport reduce urban pollution sustainably.
4. Supporting farmers with crop residue management alternatives can reduce seasonal stubble burning .
5. Improved dust control measures at construction sites mitigate particulate matter emissions effectively.
6. Integrated policy approach combining technology with systemic reforms yields long-term air quality improvement.

4. Analyse the role of regulatory frameworks in managing emerging environmental technologies and their significance in ensuring public trust and ecological safety.

1. India currently lacks a national policy standardising safety, environmental assessments, and liability for weather modification.
2. Regulations ensure operational standards, chemical usage guidelines, and post-operation impact assessments are followed.
3. Clear frameworks promote transparency, data sharing, and independent verification, building public confidence.
4. They help prevent ecological risks by mandating environmental monitoring and addressing ethical concerns.
5. Regulatory oversight balances innovation with precaution, enabling responsible deployment of emerging technologies.
6. Delhi’s cloud seeding pilot puts stress on the urgent need for comprehensive weather-modification codes by central authorities.