Delhi Likely To Witness Artificial Rain Today: What Is Cloud Seeding And How Does It Help Improve Air Quality?

Delhi government is preparing to conduct cloud seeding on Tuesday, Oct. 28, to combat the worsening air pollution. This will be the first cloud seeding trial in the national capital. The cloud seeding attempt will be carried out if weather conditions remain favourable, a PTI report said, quoting an official.   

Delhi Environment Minister Manjinder Singh Sirsa stated a review meeting has been scheduled for Tuesday to assess the feasibility of conducting the trial.

Sirsa had said on Monday that the cloud seeding trial would be conducted if weather conditions were favourable.

Delhi air quality has been worsening since Diwali, with the Air Quality Index (AQI) reaching alarming levels in many areas. The air quality in the national capital dipped to the ‘very poor’ category on Tuesday morning with an AQI of 306 at 8:30 a.m., as per the Early Warning System for Delhi. Areas like Wazirpur, Sirifort, Ashok Vihar and Bawana recorded the worst air quality with AQI ranging between 340 to 350.

Preparations for the cloud seeding experiments have now been completed, with the government conducting a test flight over Burari last week, the PTI report added, citing officials.

During the test run, small quantities of silver iodide and sodium chloride compounds used to trigger artificial rainfall were released from the aircraft. Due to low atmospheric moisture of less than 20%, as against the 50% typically required for cloud seeding, rainfall could not be induced.

The Delhi government signed a Memorandum of Understanding (MoU) with IIT Kanpur in September to carry out five cloud seeding trials. The Directorate General of Civil Aviation (DGCA) had earlier granted permission to IIT Kanpur to conduct the trials any time between Oct. 1 and Nov. 30, as per the report.

In cloud seeding operations, a chemical compound called silver iodide is used to induce the formation of ice crystals. Silver iodide exists naturally in the environment at low concentrations and is harmful to humans.

Clouds are made up of tiny water droplets or ice crystals. Certain particles, known as condensation nuclei, help in the formation of these droplets, and subsequently, raindrops. Through the cloud seeding technique, scientists modify the weather by improving the cloud’s ability to produce rain by introducing tiny ice nuclei into certain types of subfreezing clouds.

When storm systems move through a cloud seeding project area, silver iodide particles are released into clouds to increase precipitation, like rain. Upon reaching the cloud, the silver iodide acts as a stimulator to aid in the production of rain.

During the artificial rain attempt in Delhi, a modified Cessna-206H aircraft, operated by IIT Kanpur, will release silver iodide flares into moisture-laden clouds to induce rainfall. The exercise will be carried out in the north and northwest parts of Delhi.

According to Delhi government officials, even a short spell of light artificial rain is expected to reduce the dangerous levels of suspended particulate matter (PM 2.5 and PM 10). This will also help in improving AQI levels, bringing temporary relief.