Brian Barton
Karachi, the largest city in Pakistan and the 12th largest in the world, is facing significant environmental issues due to pollution. The city's air quality has been worsening over the years, with pollution levels frequently exceeding safe limits set by the World Health Organization (WHO). This is mainly due to transport and industrial emissions, waste burning, and the inefficient use of energy. The high levels of air pollution have led to severe health issues for residents, including respiratory and cardiovascular diseases, while water pollution, noise pollution, and soil contamination further compound the environmental challenges faced by Karachi.
| Characteristics | Values |
|---|---|
| Air pollution | High levels of PM2.5, NO2, SO2, and other gaseous pollutants |
| Water pollution | Industrial effluent, chemical fertilizers, and pesticides dumped into water bodies; untreated sewage; contaminated pipelines |
| Noise pollution | Traffic noise, industrial and civil works, mechanical workshops |
| Light pollution | Light trespass, over-illumination, and astronomical interference |
| Soil contamination | Hydrocarbons, heavy metals, MTBE, herbicides, pesticides, and chlorinated hydrocarbons |
| Thermal pollution | Temperature change in natural water bodies due to human activity, such as power plant cooling |
| Visual pollution | Overhead power lines, motorway billboards, scarred landforms, open trash storage |
| Loss of vegetation | Deforestation of mangrove forests |
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What You'll Learn
Air pollution from vehicles, industry, and burning garbage
Karachi, Pakistan, is the country's largest city and the 12th largest city in the world, with nearly 15 million inhabitants. As a major economic hub, Karachi suffers from pollution-related issues common to all densely populated and rapidly developing cities.
Air pollution in Karachi is caused by transport emissions, industrial emissions, and the burning of garbage. Two-stroke engines on rickshaws and motorcycles, as well as defective or poorly maintained vehicles, are major polluters, producing carbon dioxide emissions and contributing to elevated levels of sulphur dioxide and smoke. Many vehicles in Karachi still run on diesel fuel, which produces highly polluting exhaust fumes. The high volume of road traffic, including motorcycles, auto-rickshaws, cars, wagons, mini-buses, trucks, and tractors, also contributes to noise pollution.
Karachi's industries generate a cocktail of chemicals and toxic substances, and a significant amount of industrial effluent is discharged into creeks, rivers, and the sea. Textile mill effluents, for example, are wastewater discharges from textile mills involved in wet processes such as scouring, neutralizing, and bleaching, which cause huge pollution of the water. Leather production processes also have a high environmental impact due to the heavy use of polluting chemicals.
The burning of garbage is another major source of air pollution in Karachi. Instead of disposing of garbage at the solid waste management plant, people often burn it at various residential and commercial points in the city, releasing smoke and dangerous pollutants into the atmosphere. This includes the burning of plastic, which releases toxic chemicals such as benzene, formaldehyde, mercury, cadmium, and lead.
The effects of air pollution in Karachi are severe, with elevated concentrations of PM2.5 associated with significantly increased rates of hospital admissions, particularly for cardiovascular disease. Karachi has been ranked as one of the most polluted cities in the world on certain days, and its air quality often falls into the ''unhealthy for sensitive groups' bracket.
To improve Karachi's air quality, initiatives such as fining polluting factories and encouraging the use of cleaner fuel sources could be implemented. Removing highly polluting older vehicles from the roads and improving waste management practices would also help reduce air pollution levels and protect the health of the city's inhabitants.
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Water pollution from industrial effluent and sewage
Karachi, Pakistan's largest city, is facing a severe water pollution crisis due to the discharge of industrial effluents and untreated sewage into its creeks, rivers, and the Arabian Sea. The city's industrial activities generate a significant amount of toxic waste, which is often released directly into water bodies without proper treatment. This has led to the contamination of both surface water and groundwater sources, causing ecological damage and posing risks to human health.
The textile industry, for instance, uses large volumes of water in wet processes such as dyeing and bleaching, producing wastewater high in toxic chemicals. Tanneries, which are common in Karachi, are another major source of water pollution, releasing chromium, sulfide, and other harmful substances into the environment. These chemicals have contaminated the city's creeks and rivers, such as the Lyari and Malir rivers, which act as conduits for the discharge of industrial effluents and raw sewage.
The inadequate sewage treatment infrastructure in Karachi further exacerbates the problem. The city generates approximately 420 to 500 million gallons of wastewater per day, of which only a small proportion is treated before being discharged. The prevailing sewage treatment plants operate below capacity due to insufficient transmission capabilities. As a result, untreated sewage and industrial effluent flow into the Arabian Sea, creating a "man-made disaster" for the region's marine life.
The consequences of this water pollution are evident in the decline of marine biodiversity. Local fishermen have reported a decrease in fish catch, and species such as shrimp, fish, lamp shells, and various marine invertebrates have disappeared from the waters. The pollution has also affected the mangrove forests, with untreated wastewater and sewage contributing to the loss of these critical ecosystems. Mangroves play a vital role in maintaining water quality, providing habitats for numerous species, and protecting the coastline.
To address this pressing issue, the government has proposed installing combined effluent treatment plants and enforcing environmental laws to hold industrialists accountable for their waste disposal practices. However, factory owners have expressed concerns about space limitations and the need for government support in constructing treatment plants. The ineffectiveness of existing treatment plants and the delayed implementation of new initiatives have contributed to the persistence of water pollution in Karachi, underscoring the urgent need for comprehensive and swift action.
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Noise pollution from traffic and industry
Karachi, Pakistan, is a highly populated city, with nearly 15 million inhabitants. It is also a major industrial hub, which has led to severe environmental issues, including noise pollution. Noise pollution in Karachi encompasses roadway noise, aircraft noise, industrial noise, and high-intensity sonar. The main sources of noise pollution in the city are autorickshaws, trail motorbikes, and the loud horns of public transport. Other sources include motorcycles, cars, buses, trucks, tractors, and machine drills.
Noise pollution in Karachi has significant impacts on the health and well-being of residents. A study found that 74% of hospital patients in the city reported irritation due to loud noise, with 40% experiencing headaches, 29% sleep loss, and 8% hypertension. Prolonged exposure to noise can lead to noise-induced hearing loss (NIHL), which can result in irreversible hearing impairment. Vulnerable groups such as factory workers, auto-rickshaw drivers, and traffic police personnel are particularly at risk of NIHL. In one study, 84% of traffic policemen working long hours in noisy environments showed signs of hearing loss.
Industrial noise in Pakistan is a significant issue, especially in the textile industry, steel mills, and airports in major cities. In Karachi, the average noise levels in a textile mill were found to be extremely high, with 22% of workers exposed to noise levels experiencing noise-induced hearing loss. The sheet metal industry also reported high rates of noise-induced hearing impairment, with 8% of workers affected.
Traffic noise is another major contributor to the overall noise pollution in Karachi. The rapid urbanization and increase in vehicles on the roads have led to unacceptable noise levels, particularly during morning and evening peak hours. The noise levels in some areas of the city have been recorded as high as 70-95 dB, which is well above the permissible limits.
The effects of noise pollution go beyond hearing loss and include various psychological and pathological impacts. Exposure to noise can lead to mood changes, anxiety, sleep disturbances, and reduced work efficiency. It can also cause platelet clumping, which may contribute to cardiovascular ailments.
To mitigate the impact of noise pollution, immediate measures are necessary, including the maintenance and regular servicing of vehicles, the installation of silencers, and the implementation of controlling barriers between noise sources and receivers. Raising awareness among the local community and enforcing strict noise pollution laws are also crucial steps in reducing noise pollution in Karachi.
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Soil contamination from chemical spills and untreated waste
Karachi, Pakistan, is a highly populated city, with nearly 15 million inhabitants. It is also a major industrial hub, with over 6,000 industrial units operating in the city. These factors, coupled with lax environmental oversight, have led to severe environmental issues, particularly regarding air, water, and soil pollution.
Soil contamination occurs when chemicals are released by spill or underground leakage. Karachi's soil has been contaminated by various sources, including industrial activities and waste disposal practices. One of the significant contributors to soil contamination in Karachi is the indiscriminate disposal of industrial and urban waste. The city's industries discharge large volumes of untreated effluents containing chemicals and toxic substances into nearby water bodies, which eventually seep into and contaminate the soil. This includes the discharge of wastewater from tanneries, textile mills, chemical, pharmaceutical, and metal industries, which contain high levels of chromium, sulfides, fats, solid wastes, and other pollutants.
The improper disposal of domestic and industrial waste has also led to soil contamination in Karachi. The city has faced issues with garbage disposal, with residents burning garbage at residential and commercial points, releasing pollutants into the soil and air. Furthermore, the prevalent use of government-subsidized fertilizers in agriculture has contributed to the percolation of heavy metals into the soil.
The contamination of soil in Karachi has had serious repercussions for its residents. Naya Nazimabad, a neighbourhood in Karachi, was developed on contaminated land, resulting in significant health issues for its residents. The specific health impacts of living on contaminated soil can vary depending on the type and concentration of pollutants present. However, exposure to contaminated soil can generally lead to both short-term and long-term health effects, including respiratory problems, skin irritation, and an increased risk of developing certain cancers.
To address the issue of soil contamination in Karachi, it is essential to implement stricter environmental regulations and improve waste management practices. This includes ensuring proper disposal and treatment of industrial and domestic waste, reducing the use of toxic chemicals in industrial processes, and promoting sustainable agricultural practices to minimize the use of harmful fertilizers and pesticides. Additionally, regular soil testing and remediation efforts are crucial to identify and mitigate contaminated sites, thereby reducing the potential health risks for residents.
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Light pollution from artificial lighting
Karachi, Pakistan's largest city, is a bustling metropolis with a population of nearly 15 million people. As with any large and densely populated city, Karachi faces several environmental challenges, including light pollution from artificial lighting.
Light pollution, a significant issue in urban areas, refers to the excessive or inappropriate use of artificial lighting. It is caused by inefficient or unnecessary lighting fixtures that direct light upwards or outwards instead of focusing it downwards where it is needed. Common sources of light pollution include street lamps, parking lot lights, exterior lights on homes and businesses, and illuminated signs.
The effects of light pollution extend beyond just being a nuisance. It disrupts natural light patterns, compromising human health and ecosystems. For humans, light pollution can interfere with circadian rhythms, the internal 24-hour clock that regulates sleep-wake cycles and other physiological processes. Studies have linked disrupted circadian rhythms to various health issues, including sleep disorders, depression, hypertension, attention deficit disorder, obesity, diabetes, and heart disease.
Additionally, light pollution can impact wildlife behaviour and ecosystems. A study on blackbirds in Germany found that artificial lighting caused birds in cities to become active earlier than those in natural areas. Light pollution has also been shown to affect migration patterns and habitat formation in birds and sea turtles, with many insects being drawn to artificial lights and dying upon contact.
To mitigate light pollution, simple steps can be taken, such as adjusting light fixtures to direct light downwards, using fully shielded light fixtures, and employing more appropriate light bulbs. Public education and legislative changes are also crucial in addressing this issue. By implementing these measures, Karachi can reduce the adverse effects of light pollution on its environment and its residents' well-being.
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Frequently asked questions
Karachi is the largest city in Pakistan and the 12th largest in the world. The city has been facing a significant air pollution problem, with its air quality index (AQI) often among the highest globally. In 2019, Karachi's PM2.5 reading was 40.2 μg/m³, placing it as the 9th most polluted city in Pakistan and 231st worldwide.
The major sources of air pollution in Karachi include transport and industrial emissions, waste burning, generators, emissions from refrigerators, dust blowing, and stoves used in homes and hotels. 70% of the city's air pollution is emitted by motor vehicles, with two-stroke engines and defective or poorly maintained vehicles being major polluters.
The high levels of air pollution in Karachi have been linked to various health issues. Studies have shown elevated rates of hospital admissions, particularly for cardiovascular disease, on days with high PM2.5 concentrations. Air pollution has also been associated with respiratory illnesses and other respiratory diseases.
Water pollution in Karachi is increasing due to the growing economy and population, as well as the lack of water treatment. Sources of water pollution include industrial effluent being dumped into lakes and rivers, untreated sewage, and contaminated pipelines. This has led to increased waterborne diseases and infant deaths.
Karachi also faces issues such as noise pollution, light pollution, soil contamination, and deforestation. The city has also faced criticism for its plans to build a nuclear reactor, which raises concerns about thermal pollution and the untested design of the power plants.
