Understanding the Context

As autumn fades into winter, Delhi’s skyline once again transforms into a toxic haze. With Air Quality Index (AQI) levels frequently breaching the “hazardous” category, urgent measures to cleanse the air dominate public discourse. Among the latest attempts was a cloud seeding experiment on October 28, 2025, aimed at inducing artificial rainfall to wash away pollutants. However, the experiment failed to yield significant results — highlighting both the complexity of air pollution and the limitations of technological quick fixes.

What Is Cloud Seeding?

Cloud seeding is a weather modification technique designed to stimulate rainfall by dispersing certain substances into the atmosphere. These substances — typically silver iodide, potassium iodide, or sodium chloride — act as “cloud condensation nuclei” (CCN) or “ice nuclei”, around which water vapour can condense or freeze, forming larger droplets that eventually fall as rain.

The process works only when suitable clouds already exist in the atmosphere. Using aircraft or ground-based generators, these particles are released into the target clouds. If the atmospheric conditions are favourable — adequate moisture, right temperature, and updraft strength — the seeded particles encourage droplet growth and precipitation.

Cloud seeding has been successfully used across the world, particularly in China, the United States, and the UAE, for augmenting water availability or combating drought. In India, states like Maharashtra and Karnataka have employed it to enhance rainfall in drought-prone areas.

How Cloud Seeding Relates to Air Pollution Control

The logic behind using cloud seeding to fight air pollution lies in the “washing effect” of rainfall — when rain droplets capture airborne pollutants like dust, soot, and particulate matter, pulling them down to the ground. This process can temporarily clear the air, reducing PM2.5 and PM10 concentrations.

However, scientific evidence suggests that the effectiveness of cloud seeding for pollution control is limited and short-lived. Rainfall, natural or artificial, provides only temporary relief, and the pollutants soon reaccumulate if their sources remain unchecked. Moreover, the success of cloud seeding is highly weather-dependent — it cannot create rain where clouds are absent or too dry.

Delhi’s Air Pollution Puzzle

Delhi’s worsening air quality each year is not a mystery but a well-documented, recurring environmental crisis. According to studies by IIT Delhi, TERI, and SAFAR, pollution peaks in October and November due to a confluence of anthropogenic and meteorological factors:

• Stubble Burning: Post-harvest burning of paddy residues in Punjab and Haryana releases vast quantities of smoke and particulate matter that drift toward Delhi.
• Vehicular Emissions: Delhi’s dense traffic remains a major source of nitrogen oxides, carbon monoxide, and PM2.5.
• Industrial and Construction Dust: Emissions from factories, road dust, and ongoing construction projects add to the particulate load.
• Weather Conditions: During early winter, temperature inversion traps pollutants close to the ground, preventing their dispersion.

Short-Term Fixes vs Long-Term Solutions

Over the years, Delhi has tried several emergency interventions — from smog towers and anti-smog guns to the odd-even vehicle scheme and now cloud seeding. While these measures reflect the urgency to act, they often divert attention and resources from comprehensive, structural reforms.

Air pollution is not a seasonal problem but a systemic one, rooted in our energy use, transport choices, agricultural practices, and waste management systems. A one-off technological solution cannot address such deeply intertwined issues.

What Delhi Needs: A Long-Term, Integrated Approach

1. Strengthening Governance Mechanisms
   The Commission for Air Quality Management (CAQM) must be empowered to ensure cross-state coordination, real-time monitoring, and data-driven policy decisions that transcend political and administrative boundaries.
2. Sustainable Agricultural Practices
   Incentivising crop diversification, stubble management technologies, and biomass utilization can drastically cut down residue burning in northern India.
3. Cleaner Transport Systems
   Promoting electric mobility, improving public transport infrastructure, and enforcing vehicular emission norms can reduce Delhi’s road-based emissions.
4. Urban Dust and Industrial Regulation
   Stricter regulation of construction activities, industrial emissions, and waste burning is essential. Regular audits and penalties for violations must be implemented transparently.
5. Leveraging Science and Technology
   Tools such as AI-based emission tracking, low-cost air quality sensors, and satellite-based forecasting can enable more responsive and targeted interventions.
6. Public Awareness and Behavioural Change
   Air pollution control also requires citizen participation — from reducing private vehicle use to supporting waste segregation and energy conservation practices.

Conclusion: Beyond the Mirage of Artificial Rain

The failure of Delhi’s cloud seeding experiment is not merely a technological setback but a reminder of misplaced expectations. Artificial rainfall can offer temporary relief, but the real solution lies in systemic reform and sustained execution of existing policies.

India possesses the scientific knowledge, policy framework, and technological capacity to combat air pollution. What remains crucial is institutional coordination, political will, and long-term public engagement to ensure that Delhi’s blue skies are not a seasonal exception but a permanent reality.

In essence:
Cloud seeding may make the skies rain, but only strong governance and sustainable practices can make the air truly clean.

Practice Mcq’s

Question 1

Which of the following chemicals is/are used as a dispersing substance in the process of cloud seeding? 

1. Silver iodide
2. Sodium chloride
3. Dry ice (Solid Carbon Dioxide)
4. Ammonium nitrate 

Options:
(a) 1 only
(b) 1 and 2 only
(c) 1, 2 and 3 only
(d) 2, 3 and 4 only 

Correct Answer: (c)

• Explanation: Silver iodide, sodium chloride, and dry ice are common seeding agents. 

Question 2

Regarding cloud seeding, consider the following statements: 

1. It is a weather modification technique that enhances a cloud’s ability to produce rain or snow by introducing tiny ice nuclei into specific subfreezing clouds.
2. Silver iodide is frequently used due to its crystal structure resembling ice.
3. Cloud seeding guarantees rainfall even without existing clouds. 

Which statement(s) above is/are correct?
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3 

Correct Answer: (b)

• Explanation: Cloud seeding requires existing clouds; it cannot create rain from clear skies. Statements 1 and 2 accurately describe the process and a key seeding agent. 

Question 3

What is the main goal of the ‘static cloud seeding’ method?
(a) To boost vertical air currents to encourage more water to pass through clouds.
(b) To disperse salts in the lower portions of clouds to absorb water vapor.
(c) To introduce a chemical like silver iodide to provide a crystal around which moisture can condense in cold clouds.
(d) To thin high-altitude cirrus clouds to allow more heat to escape into space. 

Correct Answer: (c)

• Explanation: Static cloud seeding uses substances like silver iodide in supercooled clouds to form ice crystals, promoting precipitation. Other options describe different methods.