The air quality in Delhi remained in the poor category on Wednesday, with a thick layer of smog continuing to envelope the city and the adjoining National Capital Region (NCR) after the cloud seeding done in parts of the region failed to cause any significant rainfall or drop in pollution levels. On Wednesday at 8 am, Delhi recorded its average Air Quality Index (AQI) at 306 in the 'very poor' category, a slight rise from Tuesday's 294, which fell in the 'poor' category, according to the Central Pollution Control Board (CPCB).
Delhi cloud seeding: Did it reduce pollution?
After a gap of 53 years, Delhi carried out cloud seeding trials on Tuesday to induce artificial rain amid worsening pollution levels, although the weather department reported no measurable rainfall in the city. The Delhi government, in collaboration with IIT-Kanpur, conducted the trials in several areas, including Burari, north Karol Bagh, Mayur Vihar, and Badli, with more operations planned over the coming days, Environment Minister Manjinder Singh Sirsa said.
In a report released later in the evening, the government stated that the cloud seeding trials led to a reduction in particulate matter at the test locations, even though the weather conditions were not ideal.
According to the report, two minor precipitation events were recorded, Noida at 4 pm (0.1 mm of rain) and Greater Noida at 4 pm (0.2 mm).
"Before cloud seeding, the PM2.5 levels were 221, 230, and 229 in Mayur Vihar, Karol Bagh, and Burari, respectively, which dropped to 207, 206, and 203 after the first round of seeding. Similarly, PM10 levels declined from 207, 206, and 209 to 177, 163, and 177 at Mayur Vihar, Karol Bagh, and Burari, respectively," the report claimed.
The government added that the moisture content predicted by the India Meteorological Department (IMD) and other agencies remained low at 10-15 per cent, which is not considered favourable for cloud seeding. However, IMD data showed that no rainfall was recorded in Delhi until late evening.
How cloud seeding was done in Delhi
Explaining how the exercise was conducted, Environment Minister Manjinder Singh Sirsa said a Cessna aircraft took off from Kanpur and released eight fire flares, each weighing between 2 and 2.5 kilograms, during a half-hour trial.
Each flare burned for about two to two and a half minutes, he said. "The clouds had a humidity level of 15 to 20 per cent. The flares were released for around 17 to 18 minutes," Sirsa added.
Officials said the aircraft released silver iodide and sodium chloride compounds during the trial to trigger artificial rainfall. The second trial was also conducted later in the day in outer Delhi and covered areas like Badli. Eight flares were fired during the exercise.
Nine to 10 such trials are planned over the next few days, Sirsa said, adding that since the IMD has informed that the wind direction is towards north, areas falling under that region are being targeted.