Areas affected by smog:
Smog can form in almost any climate where industries or cities release large amounts of air pollution, such as smoke or gases. However, it is worse during periods of warmer, sunnier weather when the upper air is warm enough to inhibit vertical circulation. It is especially prevalent in geologic basins encircled by hills or mountains. It often stays for an extended period of time over densely populated cities or urban areas, and can build up to dangerous levels.


According to the Canadian Science Smog Assessment published in 2012, smog is responsible for detrimental effects on human and ecosystem health, as well as socioeconomic well-being across the country. It was estimated that the province of Ontariosustains $201 million in damages annually for selected crops, and an estimated tourism revenue degradation of $7.5 million in Vancouver and $1.32 million in The Fraser Valley due to decreased visibility. Air pollution in British Columbia is of particular concern, especially in the Fraser Valley, because of a meteorological effect called Inversion which decreases air dispersion and leads to smog concentration.
Delhi, India:
During the autumn and winter months, some 500 million tons of crop residue are burnt, and winds blow from India's north and northwest towards east.This aerial view shows India's annual crop burning, resulting in smoke and air pollution over Delhi and adjoining areas.
Delhi is the most polluted city in the world and according to one estimate, air pollution causes the death of about 10,500 people in Delhi every year. During 2013–14, peak levels of fine particulate matter (PM) in Delhi increased by about 44%, primarily due to high vehicular and industrial emissions, construction work and crop burning in adjoining states.Delhi has the highest level of the airborne particulate matter, PM2.5 considered most harmful to health, with 153 micrograms Rising air pollution level has significantly increased lung-related ailments (especially asthma and lung cancer) among Delhi's children and women.The dense smog in Delhi during winter season results in major air and rail traffic disruptions every year.According to Indian meteorologists, the average maximum temperature in Delhi during winters has declined notably since 1998 due to rising air pollution.
Environmentalists have criticised the Delhi government for not doing enough to curb air pollution and to inform people about air quality issues.Most of Delhi's residents are unaware of alarming levels of air pollution in the city and the health risks associated with it. Since the mid-1990s, Delhi has undertaken some measures to curb air pollution – Delhi has the third highest quantity of trees among Indian cities and the Delhi Transport Corporation operates the world's largest fleet of environmentally friendly compressed natural gas (CNG) buses. In 1996, the Centre for Science and Environment(CSE) started a public interest litigation in the Supreme Court of India that ordered the conversion of Delhi's fleet of buses and taxis to run on CNG and banned the use of leaded petrol in 1998. In 2003, Delhi won the United States Department of Energy's first 'Clean Cities International Partner of the Year' award for its "bold efforts to curb air pollution and support alternative fuel initiatives".The Delhi Metro has also been credited for significantly reducing air pollutants in the city.
However, according to several authors, most of these gains have been lost, especially due to stubble burning, rise in market share of diesel cars and a considerable decline in bus ridership.According to CUE and System of Air Quality Weather Forecasting and Research (SAFER), burning of agricultural waste in nearby Punjab, Haryana and Uttar Pradesh regions results in severe intensification of smog over Delhi.The state government of adjoining Uttar Pradesh is considering imposing a ban on crop burning to reduce pollution in Delhi NCR and an environmental panel has appealed to India's Supreme Court to impose a 30% cess on diesel cars.

Beijing, ChinaEdit

United Kingdom,Edit

In 1306, concerns over air pollution were sufficient for Edward I to (briefly) ban coal fires in London.[3] In 1661, John Evelyn's Fumifugium suggested burning fragrant wood instead of mineral coal, which he believed would reduce coughing. The "Ballad of Gresham College" the same year describes how the smoke "does our lungs and spirits choke, Our hanging spoil, and rust our iron."
Severe episodes of smog continued in the 19th and 20th centuries, mainly in the winter, and were nicknamed "pea-soupers," from the phrase "as thick as pea soup." The Great Smog of 1952 darkened the streets of London and killed approximately 4,000 people in the short time of 4 days (a further 8,000 died from its effects in the following weeks and months). Initially a flu epidemic was blamed for the loss of life.
In 1956 the Clean Air Act started legally enforcing smokeless zones in the capital. There were areas where no soft coal was allowed to be burned in homes or in businesses, only coke, which produces no smoke. Because of the smokeless zones, reduced levels of sooty particulates eliminated the intense and persistent London smog.
It was after this that the great clean-up of London began. One by one, historical buildings which, during the previous two centuries had gradually completely blackened externally, had their stone facades cleaned and restored to their original appearance. Victorian buildings whose appearance changed dramatically after cleaning included the British Museum of Natural History. A more recent example was the Palace of Westminster, which was cleaned in the 1980s. A notable exception to the restoration trend was 10 Downing Street, whose bricks upon cleaning in the late 1950s proved to be naturally yellow; the smog-derived black colour of the façade was considered so iconic that the bricks were painted black to preserve the image.Smog caused by traffic pollution, however, does still occur in modern London.

Other areasEdit

Other areas of the United Kingdom were affected by smog, especially heavily industrialised areas.
The cities of Glasgow and Edinburgh, in Scotland, suffered smoke-laden fogs in 1909. Des Voeux, commonly credited with creating the "smog" moniker, presented a paper in 1911 to the Manchester Conference of the Smoke Abatement League of Great Britain about the fogs and resulting deaths.
One Birmingham resident described near black-out conditions in the 1900s before the Clean Air Act, with visibility so poor that cyclists had to dismount and walk in order to stay on the road.
On 29 April 2015, the UK Supreme Court ruled that the government must take immediate action to cut air pollution,following a case brought by environmental lawyers at ClientEarth.
Mexico City, Mexico:
Due to its location in a highland "bowl", cold air sinks down onto the urban area of Mexico City, trapping industrial and vehicle pollution underneath, and turning it into the most infamously smog-plagued city of Latin America. Within one generation, the city has changed from being known for some of the cleanest air of the world into one with some of the worst pollution, with pollutants like nitrogen dioxide being double or even triple international standards.

Santiago, ChileEdit

Similar to Mexico City, the air pollution of Santiago valley, located between the Andesand the Chilean Coast Range, turn it into the most infamously smog-plagued city of South America. Other aggravates of the situation reside in its high latitude (31 degrees South) and dry weather during most of the year.

Tehran, IranEdit

In December 2005, schools and public offices had to close in Tehran and 1600 people were taken to hospital, in a severe smog blamed largely on unfiltered car exhaust.
United States:
Smog was brought to the attention of the general US public in 1933 with the publication of the book "Stop That Smoke", by Henry Obermeyer, a New York public utility official, in which he pointed out the effect on human life and even the destruction of 3,000 acres (12 km2) of a farmer's spinach crop.Since then, the United States Environmental Protection Agency has designated over 300 U.S. counties to be non-attainment areas for one or more pollutants tracked as part of the National Ambient Air Quality Standards.These areas are largely clustered around large metropolitan areas, with the largest contiguous non-attainment zones in California and the Northeast. Various U.S. and Canadian government agencies collaborate to produce real-time air quality maps and forecasts.[74] To combat smog conditions, localities may declare "smog alert" days, such as in the Spare the Air program in the San Francisco Bay Area.

Los Angeles and the San Joaquin ValleyEdit

Because of their locations in low basins surrounded by mountains, Los Angeles and the San Joaquin Valley are notorious for their smog. The millions of vehicles in these regions combined with the additional effects of the San Francisco Bay and Los Angeles/Long Beach port complexes frequently contribute to further air pollution.
Los Angeles in particular is strongly predisposed to accumulation of smog, because of peculiarities of its geography and weather patterns. Los Angeles is situated in a flat basin with ocean on one side and mountain ranges on three sides. A nearby cold ocean current depresses surface air temperatures in the area, resulting in an inversion layer: a phenomenon where air temperature increases, instead of decreasing, with altitude, suppressing thermals and restricting vertical convection. All taken together, this results in a relatively thin, enclosed layer of air above the city that cannot easily escape out of the basin and tends to accumulate pollution.
Though Los Angeles was one of the best known cities suffering from transportation smog for much of the 20th century, so much so that it was sometimes said that Los Angeles was a synonym for smog,[75] strict regulations by government agencies overseeing this problem, including tight restrictions on allowed emissions levels for all new cars sold in California and mandatory regular emission tests of older vehicles, resulted in significant improvements in air quality. For example, air concentrations of volatile organic compounds declined by a factor of 50 between 1962 and 2012.Concentrations of air pollutants such as nitrous oxides and ozone declined by 70% to 80% over the same period of time.

Major incidents in the USEdit

  • 1943, July 26, Los Angeles, California: A smog so sudden and severe that "Los Angeles residents believe the Japanese are attacking them with chemical warfare."
  • 1948, October 30–31, Donora, Pennsylvania: 20 died, 600 hospitalized, thousands more stricken. Lawsuits were not settled until 1951.
  • 1966, November 24, New York City, New York: Smog kills at least 169[81] people.

Ulaanbaatar, MongoliaEdit

In the late 1990s, massive immigration to Ulaanbaatar from the countryside began. An estimated 150,000 households, mainly living in traditional Mongolian gers on the outskirts of Ulaanbaatar, burn wood and coal (some poor families burn even car tires and trash) to heat themselves during the harsh winter, which lasts from October to April, since these outskirts are not connected to the city's central heating system. A temporary solution to decrease smog was proposed in the form of stoves with improved efficiency, although with no visible results. Coal-fired ger stoves release high levels of ash and other particulate matter (PM). When inhaled, these particles can settle in the lungs and respiratory tract and cause health problems. At two to 10 times above Mongolian and international air quality standards, Ulaanbaatar's PM rates are among the worst in the world, according to a December 2009 World Bank report. The Asian Development Bank (ADB) estimates that health costs related to this air pollution account for as much as 4 percent of Mongolia's GDP.
Southeast Asia:
Smog is a regular problem in Southeast Asiacaused by land and forest fires in Indonesia, especially Sumatra and Kalimantan, although the term haze is preferred in describing the problem. Farmers and plantation owners are usually responsible for the fires, which they use to clear tracts of land for further plantings. Those fires mainly affect Brunei, Indonesia, Philippines, Malaysia, Singapore and Thailand, and occasionally Guam and Saipan. The economic losses of the fires in 1997 have been estimated at more than US$9 billion.This includes damages in agriculture production, destruction of forest lands, health, transportation, tourism, and other economic endeavours. Not included are social, environmental, and psychological problems and long-term health effects. The second-latest bout of haze to occur in Malaysia, Singapore and the Malacca Straitsis in October 2006, and was caused by smoke from fires in Indonesia being blown across the Straits of Malacca by south-westerly winds. A similar haze has occurred in June 2013, with the PSI setting a new record in Singapore on June 21 at 12pm with a reading of 401, which is in the "Hazardous" range.
The Association of Southeast Asian Nations(ASEAN) reacted. In 2002, the Agreement on Transboundary Haze Pollution was signed between all ASEAN nations.ASEAN formed a Regional Haze Action Plan (RHAP) and established a co-ordination and support unit (CSU).RHAP, with the help of Canada, established a monitoring and warning system for forest/vegetation fires and implemented a Fire Danger Rating System (FDRS). The Malaysian Meteorological Department (MMD) has issued a daily rating of fire danger since September 2003.Indonesia has been ineffective at enforcing legal policies on errant farmers.
Since start of winter season heavy smog loaded with pollutants covered major part of Punjab especially the city of Lahore,causing breathing problems and disrupting normal traffic.
Doctors advised residents to stay indoors and wear facemasks outside.