Air Pollution in Northeast India

Air pollution is a growing concern in India. A 2017 World Health Organization (WHO) report stated that 14 of the 15 most polluted cities in the world based on particulate matter (PM) 2.5 levels were in India with Kanpur taking the ignominious lead followed by Faridabad, Varanasi and Gaya. In PM 10 level, Delhi had the worst pollution in the world with Mumbai coming in fourth. The same report revealed that 9 in 10 people in the world breathe polluted air. It also said that an estimated 7 million people die each year due to pollution-related health complications. In 2016, the report said, an estimated 4.2 million people succumbed to diseases caused by ambient air pollution while 3.8 million died due to the effects of indoor air pollution caused by firewood burning.

Air Pollution In North East India

Like the rest of the country, air quality in the northeastern region of India is on a steady decline. Thanks to rampant industrialization and urbanization in the 8 states that make up the northeast, air pollution is increasing at an alarming rate. This has led to widespread concern among the local citizens. People are looking for ways to curb pollution and guard against its ill-effects. They are drawn more than ever to the idea of air purifiers in their homes and cars. In fact, manufacturers are seeing an increase in the sale of air purification systems lately. One reason for this is the rise of respiratory diseases in the northeast. For instance, take Acute Respiratory Infection (ARI) fatalities. ARI is a serious respiratory tract disorder. It interferes with normal breathing and mostly afflicts children under the age of five. Health experts attribute ARI to an increase in PM 2.5 and PM 10 levels in the atmosphere. ARI cases in the northeast are at an all time high and this has the authorities worried.

Sharad Gokhale, professor of Environmental Engineering at Department of Civil Engineering in IIT Guwahati says, “The rising levels of PM 2.5 and soot particles in the atmosphere are responsible for the ARI cases. The link between asthma and the rising PM 10 and NOlevels already were observed in the UK. In the study ‘Urban black carbon emission – Its global impact and local mitigation’ by IIT Guwahati, we observed the pollution levels are rising, particularly in winter and post-monsoon seasons. Several development activities in and around Guwahati are adding to the increasing particle levels. Further, pollens from local vegetation may also be a cause for the increase in asthma cases. ”The Central Bureau of Health Intelligence (CBHI) recently released the National Health Profile, 2018. According to the report,Assam has the highest number of deaths due to ARI-related ailments in the northeast.The report states that in 2016, Assam recorded a total of 20,667 ARI cases and 200 deaths. In 2017 the state recorded 22,834 ARI cases and 225 deaths. Tripura recorded 7 ARI deaths in 2016 but in 2017, it shot to 21. The other north eastern states display a similar trend proving that air quality in the region is fast deteriorating. Here are the 2016 and 2017 records of ARI cases and deaths released by the CBHI.

State/UT wise Cases andDeaths due to Acute Respiratory Infection in India, 2016

State/UT wise Cases andDeaths due to Acute Respiratory Infection in India, 2016

State/UT wise Cases andDeaths due to Acute Respiratory Infection in India, 2017

State/UT wise Cases andDeaths due to Acute Respiratory Infection in India, 2017?

The findings of the CBHI have been corroborated by independent studies done by various organizations. A recent research conducted on vehicular black carbon emission in 2016-17 in Guwahati revealed some disturbing facts. It stated that the PM 2.5 level in the busy Lachit Nagararea of the city in the winter of 2016 was 111.295 micrograms per cubic meter(?g/m3). This is 11 times higher than the safe limit of 10 ?g/m3set by WHO and almost 3 times higher than the national standard of 40?g/m3 fixed by the National Ambient Air Quality Standard.

Alarmed by such grim statistics, governments at both the centre and the states are rushing to put in place checks and balances to control air pollution. Already there are approximately 573 pollution monitoring stations in 240 cities across India measuring 8 key air pollutants on a daily basis. These include PM 10, PM 2.5, sulphur dioxide,nitrogen dioxide, nitric acid, carbon monoxide, ozone and lead. The Central Pollution Control Board and the State Pollution Control Boards keep a close tab on air pollution levels through these stations.There are 2 kinds of stations: manual and automated.The manual stations calculate AQI by manually feeding the air quality data into the AQI calculator which then generates the AQI for that location. The automated stations are driven by the internet and monitor air quality on a continuous basis. They take in air quality data of the last 24 hours to calculate real-time AQI. Currently, web-based continuous air quality monitoring stations are installed in at least 10 Indian cities. Efforts are underway to install automated monitoring stations in all state capitals and 46 cities with populations of over a million.

Major Air Pollutants

Here are some of the key contributors to air pollution.

Sulphur Dioxide

Sulphur dioxide is one of the deadliest air pollutants. It is a poisonous gas released by the burning of fossil fuels.Thermal power stations and automobiles pump huge amounts of sulphur dioxide into the air. The gas reacts with other substances in the air in the presence of sunlight to produce acid rain and smog which further aggravate the problem of air pollution.

Carbon monoxide

It is a colorless, odorless and tasteless toxic gas released by the incomplete combustion of fossil fuels. It causes heart pain, giddiness, headache and fatigue. If inhaled in large amounts, it can even cause death.

Carbon dioxide

The earth’s atmosphere naturally contains carbon dioxide (CO2). But when the concentration of CO2 exceeds the safe limit, it can cause irremediable harm to the environment. CO2 is released when fossil fuels are burnt. It is a greenhouse gas and green house gases trap heat radiated from the earth’s surface to keep the surface temperatures warm to sustain life. This is known as the greenhouse effect. But when there is too much CO2 in the air, more heat gets trapped and the troposphere becomes inordinately warm resulting in global warming.

Oxides of nitrogen

Oxides of nitrogen like nitric oxide (NO),nitrogen dioxide (NO2) and nitrous oxide (N2O) are released during the combustion of fossil fuels. They are poisonous gases generated by thermal power plants, dynamite explosions in mines, and smelting and welding activities. They are also released by household cooking methods involving firewood and dung cakes. 

Volatile organic compounds (VOCs)

Volatile organic compounds are, as the name suggests, extremely volatile chemicals that evaporate at normal room temperature and pressure conditions. They are a group of compounds made up of hydrogen, carbon, oxygen, sulphur, nitrogen, bromide, chlorine and fluorine. VOCs are released by household products like cleaning supplies, paints, glues,thinners, varnishes, deodorants, room fresheners, plastic bags and plywood cabinetry. They are also released during combustion of fossil fuels. VOCs are a major cause of indoor air pollution mostly in urban houses.   

Particulate matter

Particulate matter is a family of ultra-fine solid, liquid and gaseous particles suspended in the air. They are denoted by the acronym PM. PM 2.5 and PM 10 are the most commonly measured air pollutants. The numbers 2.5 and 10 indicate the diameter of the particle.Examples of particulate matter are dust, pollen, spores, fly ash, smog, soot,cigarette smoke, bacteria, viruses, pet dander, oil smoke, heavy dust and suspended atmospheric dust. Particulate matter is a serious health hazard and a leading cause of air pollution all over the world.    


Hydrocarbons are made up of carbon and hydrogen atoms. They are a key ingredient of fossil fuels and are released when the fuels are burnt. Methane, a common hydrocarbon, is a greenhouse gas and a notorious contributor of air pollution. It is produced naturally in the intestines of ruminants like cows, buffaloes, sheep and goats, and is passed into the atmosphere in the form of farts. Methane and other hydrocarbons like benzene,butane, formaldehyde, ethane, propane and hexane are generated in landfills when garbage decomposes. This causes large-scale degradation of the ecosystem and adversely affects human health.

Chlorofluorocarbons or CFCs

Chlorofluorocarbons are man-made chemical consisting of carbon, chlorine and fluorine atoms. They are used in refrigeration, air conditioning, aerosol cans, fire extinguishers and a host of other industrial processes. CFCs are toxic chemicals that vitiate the environment beyond repair. CFCs, along with other pollutants like hydro chloro fluoro carbons(HCFCs) and halons, have been found to be directly responsible for the depletion of the ozone layer.


Stratospheric ozone protects life on earth from harmful UV radiation while tropospheric ozone is hazardous to health.Ground-level ozone is formed when pollutants from vehicular and industrial emissions react with one another in the presence of sunlight. Ozone affects the respiratory system in humans and causes debilitating lung diseases. It also causes blights and rots in crops, and lowers agricultural output.

Lead and other metals

Lead is a poisonous metal. It causes air pollution and affects the nervous, immune, reproductive, cardiovascular and endocrine systems in humans. Other metals that pollute the air are vanadium,cadmium, copper, nickel and manganese. They have been linked to various health problems and environmental issues.

Causes of air pollution in northeast India

Air pollution in the northeast is mostly anthropogenic, meaning man-made or caused by man. Here are the top reasons for air pollution in this part of the country.

Combustion of fossil fuels

Natural fuels like coal, petroleum and natural gas are called fossil fuel. They are formed by the fossilization of there mains of ancient plants and animals. Burning of fossil fuels and/or their derivatives use up atmospheric oxygen and release carbon dioxide. It also produces carbon monoxide, particulate matter, various oxides of nitrogen, lead and hydrocarbons, all of which are harmful to humans. This leads to air pollution and makes the air unfit for respiration. With industrial growth and the increase in the number of cars, more and more fossil fuels are getting burnt, making the air irreversibly polluted. In Tripura unchecked roadside burning of bitumen has led to widespread air pollution in the capital city of Agartala. It has lowered visibility and given rise to breathing problems among city dwellers.

Industrial development

Assam is famous for its crude oil. Oil deposits were first discovered in India by the British in the town of Digboi in Upper Assam. There they built the first oil refinery in India in 1901, and thus commenced the Indian oil industry. In the ensuing century, many more refineries opened across the state and brought in economic prosperity for the local populace. But with progress came a downside – air pollution.

Crude oil contains huge reserves of hydrocarbons which are known air pollutants. When refineries process crude oil and natural gas, they release large amounts of hydrocarbons, sulphur dioxide and particulate matter into the atmosphere. This causes extensive air pollution and alters the pristine balance of the biosphere for all time.


The northeastern states rely heavily on agriculture to drive their economy. Rice is a major crop alongside maize,millet and rubber. Assam is famous for its tea while Tripura is known for its coconut plantation. But the flip side of agriculture is pollution of the air and water. Fertilizers, pesticides, weedicides and fungicides used in agriculture have notoriously high levels of ammonia which is a volatile organic compound (VOC) and a major air pollutant. Also, cattle release methane which further pollutes the air and causes the ozone layer to deplete.


The northeastern states have generous deposits of sub-butiminous tertiary coal. A bulk of this coal comes from Meghalaya, followed by Assam, Arunachal Pradesh and Nagaland. Meghalaya, Assam and Arunachal Pradesh use open-cast or surface mining to excavate coal. This method interferes with the way ground water and surface water interact with each other, and causes irreversible harm to the biosphere. It also causes soil erosion and injects humungous amounts of particulate matter into the atmosphere. The situation in Nagaland is even worse as it still relies on primitive methods like rat-hole mining. Rat-hole mining causes extensive degradation of flora and fauna, and is a major cause of air and water pollution. It is also to be borne in mind that coal from these mines makes its way to thermal power plants for generation of electricity which further adds to the problem of air pollution. The other mineral mined in the northeast is limestone. Meghalaya has bountiful reserves of limestone and accounts for 9% of the total limestone production in the country. Assam also has a large number of limestone quarries that supply the cement factories. However, unchecked drilling and blasting activities have caused the air quality in these states to plummet and forced the authorities to take steps to mitigate the harm done.


Smoking and chewing tobacco is an intrinsic part of the lifestyle of the people of the northeast. It is also a leading cause of cancer in men in these states, mainly nasopharynx, stomach and esophageal cancer.Tobacco smoke is made up of fine particulate matter that penetrates deep inside our lungs and causes the tissues to behave abnormally. It vitiates the air we breathe and affects non-smokers too through passive inhalation. According to a recent report, 57% of the cancers in men and 28% in women in the northeastern states can directly be attributed to tobacco and betel nut consumption. It is an endemic problem that needs to be urgently addressed.

Steps taken by the government to curb air pollution in north east India

Faced by growing air pollution, the authorities in the northeast are taking urgent action to rein in air pollution.In Assam, the State Pollution Control Board (SPCB) recently inaugurated the state’s first automated continuous AQI monitoring station in Guwahati. The station will continuously calculate PM 2.5 levels and broadcast real-time air quality data through display screens in two different localities in the city. Earlier,only one station in the city had the technology to measure PM 2.5 particles. With the opening of the second station, plans are in motion to open two more such stations in the coming months. Currently, Assam has 22 AQI monitoring stations with 6 of these in Guwahati alone. Health officials are optimistic that with the new data, the SPCB will be in a better position to tackle air pollution.

Tripura is striving to curtail air pollution through eco-friendly initiatives. It has adopted a two-pronged green route to environmental restoration. On the one hand it is scaling up efforts to have more and more vehicles running on CNG (Compressed Natural Gas), and on the other, it is increasing its supply of PNG (Piped Natural gas) to households for domestic cooking. The Tripura Natural Gas Co Ltd (TNGCL), a joint venture between the Tripura and Assam governments and the Gas Authority of India Ltd (GAIL),was set up in June 1990 with the objective of replacing conventional fuels with cleaner alternatives such as CNG and PNG. Currently, around 29,000 households,360 commercial establishments and 50 industrial units have PNG connections in Tripura. TNGCL plans to extend the service to 7000 additional households. Also,around 10,000 vehicles in the state, including 5000 auto-rickshaws, run on CNG. TNGCL aims to boost this number too to cut back on fuel costs and reduce air pollution.

The Meghalaya State Pollution Control Board recently organized the Northeast Green Summit. The main objective of the Summit was to draw up an action plan to fight air and water pollution through stricter implementation of environmental laws. It was attended by the International Institute of Waste Management, the Centre for Science and Environment, the Chintan Environmental Research and Action Group, and several other NGOs and environmental experts. The Summit is an ongoing endeavour to implement environmental laws and best practices to protect and revive the ecosystem.


The air in the northeastern states of India is far from healthy. Steps need to be taken to curb this menace before it is too late. For this, a combined effort is required by the governments, civic bodies and the citizenry. Each of us is a stakeholder, and we need to do our part to make our planet a better place to live in.

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