New Delhi: Delhi’s air quality has shown no signs of improvement for a couple of weeks and as per authorities, the quality is only set to deteriorate further in the coming days. With the air pollution being a periodic issue in the region, the Ministry of Environment, Forest and Climate Change has approved inducing artificial rain by the process of cloud-seeding. The process will be carried out jointly by Central Pollution Control Board (CPCB) in association with Indian Institute of Technology – Kanpur. It is expected to wash away the pollutants present in the air and help curb the alarming levels of pollution which is a major threat to public health today.
Cloud seeding is a controversial technology which is not really fully understood by all. In simple words, cloud seeding is the process of combining different kinds of chemical agents like silver iodide, dry ice and table salt, injecting them in clouds to thicken them and increase the chances of a rainfall. The process is carried out using aircrafts and is often explained as art and science of creating artificial rain by the scientists.
The clouds required for cloud seeding are of a typical type. They are called convective clouds, and they grow vertically. Only these can be seeded, not the other type, which are called stratified and grow horizontally. They work to endorse rainfall by inducing nucleation – whatever water is in the air condenses around the newly familiarised particles and crystallises to form ice, explained IIT Kanpur Scientist and Professor, Sachchida Nand Tripathi.
The process has been tested multiple times by the scientists in the last six decades for drought mitigation and raising water levels in dams in India. It was used by the Tamil Nadu government in 1983 to 1987 and 1993-94 owing to the state’s severe drought. Karnataka government tried the procedure in 2003 and 2004 and similarly the method has been tried in Andhra Pradesh and Maharashtra. These initiatives have however received contradicting results.
When it comes to the drought hit regions, rain bearing clouds lack particles due to which the rain falls and through cloud seeding, special particles are artificially injected into monsoon clouds to make them rain.
China is also known for its notorious air quality and has been depending upon artificial rain for years. Most famously, it has become a tradition in Beijing to seed the clouds before public holidays, such as National Day on 1 October, to make it rain, disperse pollution and ensure clear skies on the day. Indian scientists are not satisfied with the Chinese plan though because it is not known if they’re successful during extreme levels of pollution and also, the experts have warned of air and water pollution as an outcome of the chemicals used in the process. The chemicals used in creating rain and clearing the air could leave behind residues of pollution.
Other than China, countries like Australia, France, Spain and the US are among the countries also known to try the method of cloud seeding.
In Delhi-NCR however, the process is yet to be tried out. The Union Environment Ministry has said it is waiting for “appropriate” level and density of clouds, and a clearance from the Indian Meteorological Department to induce artificial rain through cloud seeding in Delhi.
We have made all the preparations and have also got the aircraft from ISRO which will be needed to induce the artificial rain. The technique has been tested before in Maharashtra as well as parts of Lucknow. However, this is the first time in India that artificial rain would be created over a big land mass to counter the damage done by air pollutants, said Manindra Agarwal, Deputy Director IIT Kanpur.
The cloud seeding process will only be successful when there are enough clouds in the sky. We haven’t got the desired clouds after November 13 and 14. Once we get predictions of such dense clouds and get aircraft for that period, we’ll be ready for cloud-seeding on short notice, Professor Tripathi added.
Although artificial rain is tried and tested and is expected to help with the problem of air pollution, several environmental experts have raised concerns when it comes to the viability of the method in a long run.
Cloud-seeding might give relief from air pollution for a short span of time by washing down the pollutants from the air but for how long? In 2 or 3 days, the toxic smog will be back and then what? It is nowhere near to a solution to pollution we need to trap pollutants at source and come up with a sustainable solution to curb air pollution, Greenpeace India’s senior campaigner Sunil Dahiya told NDTV.
On the other hand, Professor Tripathi believes that short-term solutions often give birth to long-term solutions.
It is a matter of public health and naturally we have to try whatever solution is available to try. Every method is a short term solution at one point in time and out of these multiple methods, we pick one that is sustainable on a long term basis. So until we try cloud seeding, we would not know if it has the potential to even become a long term solution, Professor Tripathi said.
As per a senior CPCB official, cloud seeding will be done through an aircraft procured from ISRO which will transport and disperse the necessary silver iodide, taking off from one of three airports in NCR.
As soon as we get a go-ahead from IIT Kanpur regarding the metrological conditions, we will initiate the process. A lot of concerns regarding the feasibility of the method have been raised and we are well aware of that, but being a central body, we have to look into both long term as well as short term solutions, the CPCB official told NDTV.
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