Will Delhi govt conduct artificial rain this weekend amid worsening AQI? What we know so far

Delhi woke up to toxic air on Tuesday morning as pollution levels soared across the national capital after Diwali festivities. This prompted the state government to invoke GRAP 2 measures to curb pollution that poses risk even to healthy individuals besides those already suffering from respiratory diseases and asthma issues. On Monday, the national capital recorded an AQI of 357, according to Central Pollution Control Board data at 1:20 PM.

Since October 19, Graded Response Action Plan Stage 2 is effective in Delhi-NCR as the AQI crossed 300 on Sunday. falling in the “very poor” category. Every year, Delhi government faces the problem of hazardous air pollution during this time. However, it is time to revisit Delhi government’s pollution combat measures.

Delhi govt’s pollution combat measures post Diwali —

Few days before the festival, Environment minister Manjinder Singh Sirsa had asserted that the Delhi government is “fully prepared” to induce artificial rain in a bid to reduce air pollution around Diwali.

This announcement was made after four days of cloud seeding trial flights were conducted over the target area in northwest Delhi. At the time of the announcement, the project awaited a final green signal from the India Meteorological Department (IMD).

“Our aircraft is ready at Meerut. The pilots have familiarised themselves with the flight path. We’re only waiting for IMD’s green signal and the right cloud conditions. If all goes well, the first trial could happen even on the day-after Diwali or the following day, if conditions are suitable,” Manjinder Singh Sirsa said on October 15.

Will Delhi govt conduct artificial rain this weekend amid worsening AQI?

For administration of artificial rain, aircraft is stationed at Meerut, and pilots completed familiarisation with the flight path. The implementation of these landmark measures depends on weather conditions and IMD’s approval. If approved, the first trial could take place anytime soon.

What is Cloud seeding?

Cloud seeding refers to the process of dispersing silver iodide (AgI) and other such substances such into clouds to boost their ability to produce rain. This artificial rain induction project is being carried out in collaboration with IIT Kanpur.

Cessna-206H aircraft has been modified for this purpose. For a successful attempt ideal conditions that enable and facilitate the seeding project involve Nimbostratus clouds, which are typically between 500m and 6,000m above ground. However, these ideal clouds must contain at least 50% moisture.

Roadblocks in conducting artificial rain

Lack sufficient moisture or cloud density can delay the artificial rain procedure.

Impact on pollution after successful cloud seeding attempt

Depending on intensity and spread of artificial rain, rain can improve air quality by at most 80 AQI points. According to former head of CPCB’s air lab, Dipankar Saha, light rain or drizzle is unlikely to make a significant difference. Sustained and strong showers are needed for a “washout effect.” Experts suggest that AQI can improve by one category with a successful attempt. Example: If AQI is “very poor”, it may improve to “poor.”