In recent years the advent of winters is often coupled with a dense fog that descends early in the evening and lifts around mid-morning, if you’re lucky, in northeastern Pakistan. What is this fog? Actually, it is not fog but something called smog. In winters, the moisture in the air often gets mixed with pollutants to form smog. This is extremely hazardous for respiratory health in addition to causing difficulty in everyday life particularly commuting to and from work or educational institutes.
Smog has become the fifth season in many cities of Pakistan, especially Lahore. Lahore, Faisalabad and Gujranwala are the most populous and polluted cities of Punjab, which are also the worst affected by smog that returns every winter with a greater intensity. According to the data published in National Centre for Biotechnology Information (NCBI) journal, the Air Quality Index (AQI) in certain areas of Lahore repeatedly exceeded 400 μg/m³ in the month of November, 2021 while the safe AQI value is considered to be below 50 μg/m³. A major consequence of this deteriorated air quality in winter months is smog.
Increased level of air pollutants is thought to be responsible for the formation of smog. Air pollution has been increasing in both developed and developing countries due to the rapid urbanization and industrialization. Major contributors of air pollution are particulate matter (PM2.5 and PM10), which have harmful effects on air quality and human health. Air pollution is caused by carbon monoxide (CO), sulphur dioxide (SO2), hydrogen fluoride (HF), hydrocarbons, oxides of nitrogen (NOx), chlorofluorocarbon (CFCs), regional sources like ozone-depletion, and continuous sources like municipal waste treatment plants (where incineration takes place), emissions from electric power plants and other secondary sources. All these activities harmfully affect human health and also contribute to smog formation. 
Every year in Pakistan, farmers set fire to the straw in their freshly harvested fields. This is done to get rid of the waste before the new crop is cultivated. This fire produces ash and particles, which also travel in air to other cities and play a role in smog formation. In Punjab, which has the highest number of brick kilns, the smoke from brick kilns is said to be among the most significant causes of smog.
In recent times, various cities of Pakistan have been struck by the chaos of smog. According to the NCBI report, Pakistan is the most urbanized country in South Asia and its second largest city Lahore is growing at a rate of 4% every year. It is considered to be one of the most polluted cities in Pakistan. Urban settlements are frequently plagued by smog in Asia, and Lahore is also included in this. In 2019, the AQI of Pakistan fell into the category of ‘unhealthy’. According to the Brazilian Journal of Biology, in Pakistan, the number of deaths attributable to particulate matter (PM2.5) exposures for all ages and sexes increased from 82,300 in 1990 to 135,100 in 2015 and deaths from chronic obstructive pulmonary disease (COPD) attributable to ozone exposure increased from 1,600 in 1990 to 5,000 in 2015. In December 2021, according to the IQAir, Lahore was ranked first in the list of most polluted cities with readings as high as 453, which is considered extremely toxic.
Smog causes many serious health issues, particularly respiratory issues such as coughing, asthma exacerbation, chest irritation, burning throat and chronic bronchitis. In addition to these problems, smog also causes eye and skin manifestation and cardiac issues. Smog also hampers daily life in the form of fatalities because of poor visibility causing road accidents, flight delays, etc. The persistent anti-cyclonic conditions can further trigger the temperature inversion and prolong the smog event from days to weeks.
Smog, in addition to endangering human health, can have a wide range of environmental implications. For example, the particles in the smog result in visibility impairment, modification of nutritional balance in vast river basins and coastal waters, acidification of lakes and streams, decrease in soil nutrients, adversely impacting habitat diversity, endangering vulnerable ecosystems and augmenting the impacts of acid rain. The Ministry of Climate Change (MOCC) is concerned with climate changes at federal level, whereas, in Punjab there is the Environment Protection Department, which is responsible for monitoring air quality. MOCC has established a Smog Control Room in Lahore in order to monitor and evaluate the health hazards accompanying smog in various regions of Punjab. Smog Commission of the provincial government recommends the closure of all brick kilns in Punjab from September to December. It has also been suggested that these brick kilns be converted to the new zigzag technology, which reduces smoke and pollution. The Smog Control Room is also concerned with maintaining a check on AQI in Punjab, especially Lahore.

Certain measures were announced by the Prime Minister of Pakistan for the possible control of smog in 2019. The measures announced included that the by the end of 2020, Euro 5 fuel would be imported while the fuel already being used would be converted into Euro4, and oil refineries to be given three years to improve and adopt modern technologies. Furthermore, negotiations were held with electric vehicles manufacturers. The government was also expected to import machinery worth Rs 30 billion to help control the stubble burning issue. Moreover, the government wanted to convince owners of kilns to adopt modern zigzag technology. About 60,000 kanals area had been identified for urban forestry in Lahore in addition to other cities. The number of monitoring centers to keep a check on the air quality in Lahore was to be increased to 30 from 2 to help give more accurate data. 90% pollutants were expected to be reduced by such steps.
Smog is an environmental hazard and there is an urgent need to fight this menace for a safer future. We should try to inculcate measures suggested by WHO in order to combat air pollution including investment in energy-efficient power generation, reducing agricultural waste incineration, forest fires and certain agro-forestry activities, improving industrial and municipal waste management, greener cities with  energy-efficient buildings, building of safe and affordable public transport systems, provision of  universal access to clean affordable fuels and technologies for cooking, heating and lighting. 
Advanced technology can be employed in reducing smog, like gas to liquid technology for fuel, usage of hydrogen fuel additives, which can reduce the emission of pollutants, employing photo-catalytic materials and air purification like smog-free towers that can suck pollutants from the air and emit clean air into the atmosphere. 
The relevant bodies need to aptly employ the measures to handle the smog before its arrival. Both public and private institutions should disseminate knowledge among the populace to reduce pollution, particularly the emissions of particulate matter and nitrogen oxides. By reducing air pollution, we can tackle the world’s largest environmental health risk for non-communicable diseases. We can adopt some of the precautionary measures to stay healthy at a personal level as well like wearing a mask, avoiding being outside in high-traffic areas to reduce our exposure, avoiding doing intense outdoor work and reducing our own carbon footprint as much as possible. HH

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