What is a smog tower and why is it installed?

Delhi Chief Minister Arvind Kejriwal inaugurated "India's first smog tower in New Delhi on August 23. What is a smog tower and why is it installed? Let's find out

Improve air quality

Smog is a type of intense air pollution that reduces visibility. It is a combination of harmful pollutants such as nitrogen oxide, carbon monoxide, fine particulate matter, and ground-level ozone. Smog towers are installed to fight pollution and to filter and purify air. As we all know, Delhi is one of the most polluted cities in the world. In a bid to control pollution levels, the Delhi government has installed a smog tower at Connaught Place on an experimental basis. If the pilot project is found to yield results, many such structures can be expected to come up around the capital.

The 24-metre tall steel-and-concrete smog tower, built at a cost of Rs. 20 crore, has 40 huge fans and 5,000 filters. It will suck in polluted air from above and pass it through filters fitted at the bottom. It is believed to be able to purify up to 1,000 cubic metres of air every second within a radius of one kilometre. While the technology has been imported from America, the tower has been built by Tata Projects Limited with technical support from IIT-Delhi and IIT-Mumbai, which will analyse its data. National Buildings Construction Corporation Ltd (NBCC) is the project management consultant.

The smog tower is expected to operate at full capacity" after the monsoon season. A control room has been up at the site to monitor its operations A two-year pilot study will ascertain the efficacy of the tower


The Supreme Court in January 2020 had directed the Central government to construct a smog tower to reduce pollution at Anand Vihar, and the Delhi government to install another such structure at Connaught Place. “IQAir”, a Switzerland-based company that measures air quality levels based on the concentration of lung-damaging airborne particles known as PM2.5, had ranked Delhi the world's most polluted capital for the third consecutive year in 2020. The smog tower, built by the Central government at Anand Vihar, is expected to become operational soon According to a 2019 estimate, the capital will need over 200 such anti-smog towers.

Experts' take

The concept of smog towers does not find favour with some experts, who argue that the towers may provide immediate relief from air pollution in a small area, but are too expensive to set up. They also feel there is no scientific evidence to back the long-term benefits of smog towers. Instead renewable energy, should be promoted to tackle air pollution and reduce emissions.

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What are single-use plastics and what are the challenges in our fight against plastic pollution?

On August 13, the Environment Ministry notified the Plastic Waste Management Amendment Rules, 2021, which prohibits specific single-use plastic items that have low utility and high littering potential by 2022. The decisions follow recommendations made by an expert group constituted by the Department of Chemicals and Petrochemicals two years ago.

Under this rule, the manufacture, sale, and use of a range of plastic products will be prohibited from July 1 2022 These include ear buds with plastic sticks, plastic sticks for balloons, plastic flags candy sticks, ice cream sticks, thermocol for decoration plastic cutlery such as forks, spoons, knives, cups, plastic wrapping and packing films around sweet boxes, invitation cards, cigarette pack and PVC banners less than 10 microns. These items will be phased out in three stages.

The new rule has also increased the permitted thickness of polythene bags. They must be at least 75 microns thick from September 30, 2021, and 120 microns from December 31 next year, compared to 50 microns at present.

At the 4th United Nations Environment Assembly in 2019, India piloted a resolution on addressing single-use plastic products pollution. Later that year, in his Independence Day speech, Prime Minister Narendra Modi called on people to stop the use of single-use plastic bags.

Following this, many Indian States set deadlines to ban certain plastic products. The initial enthusiasm soon died down and banned plastic items are back in use. At about 34 lakh tonnes generated in 2019-20. India has a staggering annual volume of plastic waste, of which only about 60 % is recycled.

While environmentalists welcome the new rules, they also point out the challenges in curbing plastic pollution. What are they?

Why is plastic non-biodegradable?

 A material is biodegradable if it can be decomposed by bacteria and other living organisms. Most plastic are derived from propylene, a chemical component of petroleum. A crucial manufacturing step causes monomers (a molecule that can be bonded to other identical molecules to form a polymer) of propylene to link together and form very strong carbon-carbon bonds with each other. This results in polypropylene, which is not easily broken down by microorganisms. Thus plastic remains non-biodegradable for years.

What are single-use plastic?

Single-use plastic, or disposable plastic, are those plastic items we use only once before discarding them. Each year, 400 million tonnes of plastic is produced around the world, and 40 % of that is single-use.

Plastic is low cost, lightweight, practical, and easy to make. These qualities make it the most preferred material for producing disposable items. According to the UN Environment, the most common single-use plastic found in the environment (in order of magnitude) are cigarette butts, plastic drinking bottles, plastic bottle caps, food wrappers, plastic grocery bags, plastic lids, straws and stirrers, other types of plastic bags, and takeaway foam containers.

What happens to the plastic that we discard?

Plastic takes hundreds of years to decompose, in the meantime, it remains in the environment contaminating soil and groundwater. A lot of it also ends up in the ocean posing threat to marine life. Animals consume plastic accidentally or mistaking it for food .plastic gets lodged in their stomach and prevent their digestive system from working properly .This eventually leads to the animal death n

When they degrade plastics also leach potentially toxic chemical (additives used to shape and harden plastic) which make their way into our find and water supply systems. These toxic chemicals are now being found in our bloodstream Researches have found them to disrupt the endocrine stem which can cause cancer, birth defects impaired immunity, and many other problems.

Some plastic slowly break down into smaller pieces of plastic called microplastics and make their way into the system of marine animals and humans who ultimately consume some of these seafood Microplastics have been found in soil and air as well.

 The UN Environment Programme reports that past 9 % of the world's nine billion tonnes of plastic have been recycled.

What are the challenges ahead?

Putting an end to plastic pollution depends on various factors. Some of the challenges in implementing measures against use of plastic listed out by experts are

  • The failure to enforce rules.
  • Finding alternatives to single-use plastic items. This alternative should be sustainable too.
  • Bioplastics, which are made using a range of agricultural byproducts, are increasingly being seen as an alternative. However, bioplastics break down only in a high-temperature industrial composting facility and very few cities have the infrastructure needed to deal with them. These bioplastics often end up in landfills and oceans and pose the same risk as conventional plastic. 
  • Considerable amounts of plastic waste are not recycled because of lack of segregation and collection Only 60 % of plastic waste is collected and recycled in India, while the remaining remains littered in the environment Our policies should also focus on collection and segregation
  • The plastic recycling industry is vast and unorganised.  Most of the plastic wastes are recycled into low quality materials which again become single-use items. The recycling business would need support - technical and financial - to upgrade to alterative industry.
  •  Collaboration is required across the value chain-from design and reuse to repair and recycling-in order to develop impactful solutions.

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What are wildfires? Why are they becoming more frequent and intense across the world?

A California wildfire that closed nearly 200 square miles of forest forced evacuations across state lines into Nevada recently as winds and scorching, dry weather drove flames forward through trees and brush.

The Beckwourth Complex - which began as two lightning-caused fires in Plumas National Forest - was intense. Hot rising air formed a gigantic, smoky pyrocumulus cloud that reached thousands of feet high and created its own lightning.

In north-central Arizona, increased humidity slowed a big wildfire that posed a threat to the rural community of Crown King.

Elsewhere, Cyprus saw one of the worse wildfires since the Republic of Cyprus was established in 1960. Wildfires destroyed 50 homes, damaged power lines and forced the evacuation of 10 villages. The blaze ripped through mountain forests and farmland, killing four people and destroying scores of homes.

Water-bombing planes from Greece and Israel and British aircraft from bases on the Mediterranean island helped douse the huge fire, which blackened 55 square kilometres (21 square miles) of the Troodos Mountains.

Climate change is considered a "key driver' of a trend that is creating "longer and more intense dry seasons that increase moisture stress on vegetation and make forests more susceptible to severe wildfire," the California Department of Forestry and Fire Protection said.

What is a wildfire?

An uncontrolled fire in an area of combustible vegetation which spreads quickly, wiping out large areas of land is called a wildfire. A wildfire can also be termed a forest fire, a grass fire, a peat fire or a bush fire, depending on the type of vegetation present in the area.

What causes wildfires?

Wildfires are common in Australia, Southeast Asia, southern Africa, Western Cape of South Africa, the forested areas of the United States and Canada, and the Mediterranean Basin. During summer, when there is no rain for months, the forests become littered with dry leaves and twigs, which could be ignited by the slightest spark.

Natural causes: Lightning is the most common cause of wildfire. There are three conditions for a forest fire to spread -fuel, oxygen and a heat source. In the forest, anything that is flammable is a fuel. This includes tall, dry grass, bushes and trees. High temperature, drought and dry vegetation are a perfect combination for igniting a forest fire.

Man-made disaster: Human neglect such as downed powerlines, sparks from tools or forest machinery, abandoned campfires and discarded cigarette butts can spark fires. People also tend to clear forests by setting them on fire to pave way for cultivation. Sometimes they set fire to scare away wild animals.

How is a forest fire put out?

Traditional extinguishing methods include water dousing and spraying of fire retardants from aircraft. To limit the spread of a fire, firefighters remove ground litter and bush.

What is a heatwave?

A heatwave is a period of prolonged abnormally high surface temperatures relative to those normally expected. Classifying a heatwave varies from country to country. The World Meteorological Organisation (WMO) defines heatwaves as five or more consecutive days during which the daily maximum temperature surpasses the average maximum temperature by 5°C or more.

What is the link between climate change and forest fires?

  • Climate change has created conditions conducive to forest fires. Long summer, drought, and dry air and vegetation make forests more susceptible to severe wildfire.
  • Climate change has led to frequent heatwaves across the globe. Hotter temperatures, again, mean parched land.
  • Climate change has also lengthened the fire season in many parts of the world.

Why does California experience forest fires quite often?

California's climate: Wildfires are a natural part of its landscape. California has two distinct fire seasons- one that runs from June through September and another from October through April. While the first one is driven by a combination of warmer and drier weather, the second one is driven by dry winds which make wildfires spread rapidly and cover large areas.

Longer fire season: In the recent past, the fire season in California has been starting earlier and ending later. The length of the season is estimated to have increased by 75 days. Beetle infestation: Prolonged drought conditions leave behind a landscape of dead trees, which lead to infestation by bark-eating pests such as the mountain pine beetle. Outbreaks of pests weaken and kill trees. Beetle-killed trees are at a higher risk of fire.

Warmer weather: Heatwave is a major contributor to forest fires in California.

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Why are children more susceptible to air pollution?

Children face special risks from air pollution because their lungs are growing and because they are so active and breathe in a great deal of air.

Several studies have found air pollution linked to harm to children while they are still in the womb. A large study in California found that higher particle pollution levels increased the risk of preterm birth.5 Pregnant women exposed to even low levels of particle pollution had higher risk for preterm birth in a Boston study.6 Preterm births occurred more frequently when particle pollution spiked, as an Australian study found, even when they controlled for other risk factors.

Further evidence that cleaner air provides real benefits to children’s health came in a 2016 report from the same study exploring changes to 4,602 children’s respiratory symptoms such as coughing, congestion and phlegm. The study looked at the changes in these symptoms in three groups of children living in Southern California over different periods of time when air quality also differed (1993-2001, 1996-2004, and 2003-2012). As air quality improved, the children in the study suffered fewer bronchial symptoms whether they had asthma or not. In communities where the air quality improved the most, the children experienced even fewer symptoms.

So, does cleaning up the air really improve children’s health? In 2017, the researchers reviewed these long-term studies of children in Southern California and the impact of improvements in air quality on their health. They concluded that the 20 years of collected data provided strong evidence of the potential to improve children’s health by reducing some of the most common outdoor air pollutants.

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What is PM 2.5?

PM 2.5 refers to a category of particulate pollutant that is 2.5 microns or smaller in size. The average cross-section of a human hair is 50 microns. PM stands for “particulate matter.” The EPA and many health organizations categorize particulate matter by size because different size particles have different health effects. For instance, PM 10 particles (particles less than 10 microns in size) can irritate your nose and eyes, but fewer of these particles penetrate deep into your lungs, so they do not cause the same health problems that smaller micron particles can, although they do increase rates of respiratory disease 

PM 2.5 particles are complex because they can be made up of numerous types of chemicals and particles, and they can be partly liquid, as opposed to solid, like a common dust particle. Particulate pollutants that are entirely or partly made up of liquid droplets are known as an aerosol. Natural kinds of aerosols include dust, sea salt and volcanic ash, whereas man-made sources include factory and auto emissions, coal combustion and biomass burning for clearing land or farming.

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