Delhi’s First Artificial Rain: Can Cloud Seeding Really Clean the Capital’s Skies?

October 26, 2025

Delhi Prepares for Cloud Seeding Amid Rising Pollution

Delhi is set for its first artificial rain between October 28 and 30, as the city grapples with soaring air pollution. With PM2.5 levels hitting the highest mark since January, emergency interventions have resurfaced, including the Delhi government’s ambitious cloud seeding program aimed at washing particulate matter from the atmosphere.

Chief Minister Rekha Gupta confirmed that if weather conditions remain favourable, Delhi could witness artificial rain on October 29, marking a major technological milestone in the capital’s fight against air pollution. The program, developed in partnership with IIT Kanpur, has completed all preparatory trials, including aircraft readiness, flare tests, and coordination protocols.

A Cessna-206H aircraft, stationed in Meerut, will disperse seeding material such as silver iodide into clouds, stimulating rainfall when moisture-laden clouds are present. However, the success of the program depends entirely on the presence of sufficient clouds — clear skies cannot be seeded.

How Cloud Seeding Works

Cloud seeding is a weather modification technique designed to enhance precipitation. It involves dispersing substances like silver iodide or salt particles into clouds, which act as nuclei for water condensation. Two primary methods exist:

1. Hygroscopic Seeding: Salt-based particles are released at the base of warm clouds to encourage water droplets to merge and fall as rain.
2. Glaciogenic Seeding: Silver iodide or dry ice is injected into supercooled clouds, triggering ice crystal formation that melts and descends as rainfall.

Delhi’s seeding operation will target Nimbostratus clouds containing at least 50% moisture and located between 500 and 6,000 meters above ground, the ideal conditions for rain generation.

Potential Impact on Air Quality

Artificial rain could temporarily reduce Delhi’s Air Quality Index (AQI) by 50 to 80 points. For example, if the AQI is in the “very poor” category (300–400), rainfall might bring it down to the “poor” or “moderate” range. Rain achieves this by washing out PM2.5 and PM10 particles, which dominate Delhi’s winter pollution.

Despite these potential gains, experts stress that the relief is short-lived. Pollutants from vehicles, construction dust, industrial emissions, and crop stubble burning can quickly rebound, returning AQI levels to dangerous ranges. Cloud seeding is therefore considered a temporary intervention, not a long-term solution to systemic pollution problems.

Limitations and Criticisms

While promising, cloud seeding faces several challenges:

• Meteorological Uncertainty: Delhi’s winter skies often lack moisture-rich clouds, making rain induction unpredictable.
• Temporary Gains: Even if successful, the reduction in pollution lasts only a few days.
• Environmental Concerns: Repeated dispersal of silver iodide may pose long-term ecological risks, though regulated use is generally considered safe.
• Scientific Ambiguity: It is difficult to conclusively attribute rainfall to seeding versus natural weather processes, especially in dense urban areas. Controlled experiments with multiple aircraft and ground-based monitoring are needed, which can be challenging to execute.

Authorities such as the Central Pollution Control Board (CPCB) and the Commission for Air Quality Management (CAQM) have cautioned that cloud seeding should remain experimental and not replace structural reforms in energy, transportation, and waste management — the key drivers of Delhi’s chronic pollution.

Delhi’s Cloud Seeding in Context

Cloud seeding is not new to India. States like Maharashtra, Karnataka, Andhra Pradesh, Gujarat, and Tamil Nadu have deployed similar techniques, mainly to boost rainfall in drought-prone agricultural regions. Historical programs like CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment) suggest a 15–20% increase in rainfall under optimal conditions. However, replicating these outcomes in a dense urban environment remains largely untested.

As Delhi awaits its first artificial rain, city officials, scientists, and residents are watching closely. While cloud seeding offers a glimmer of hope, experts agree that only sustained structural changes — including pollution control, industrial regulation, and emission reduction — will provide lasting clean air for the capital.