How Guwahati Air Emerged as World's 2nd Most Polluted

Guwahati air pollution

It has been about seven years since Milin Dutta, a 54-year-old trans man, moved back to his hometown Guwahati from the United States. Earlier, when he used to come home for vacations, he would always get a cold and a dust allergy, he recalled. It took a few years for Dutta to realise he had asthma, and it got worse in Guwahati. “I used to get asthma attacks and had to take medication for it,” he said.

How accurate is the Swiss air quality report?

Anumita Roychowdhury, executive director, research and advocacy at the Centre for Science and Environment (CSE) in New Delhi, said that the Swiss air quality data for Guwahati are a bit on the higher side than the data she was able to access from the Central Pollution Control Board (CPCB).

Roychowdhury added that if the Swiss air quality report has combined Byrnihat--an industrial town in Meghalaya state on the border with Assam--it is quite possible to have a high average annual PM 2.5 concentration of 105.4 for Guwahati. We reached out to IQAir for clarity on this, and we will update the story when we receive a response.

In fact, Byrnihat was declared as the most polluted city in India during February in a dataset released by the Centre for Research on Energy and Clean Air (CREA). “We don’t know what method the Swiss air quality monitoring group has used. I have no way of verifying whether they have combined Byrnihat or are they attributing this number only to Guwahati city,” Roychowdhury explained.

But she noted that whether the Swiss air quality report is accurate or not, is not the key point. “Key point is that in Guwahati, the overall pollution levels are on the rise. Guwahati has certain geographical disadvantages: It is more like a valley surrounded by hills and in that kind of geography, there is often the tendency for the pollution concentration to be higher because the trapping bit happens, especially during winters,” she said.

Rahul Mahanta, associate professor at Cotton University’s department of physics in Guwahati, reiterated Roychowdhury’s point. He said that PM 2.5 is “basically because of black carbon, and Guwahati has had a high PM 2.5 for a while now. During the winter months, conditions change: The moisture stays, a lid forms due to cold air that flows from the hills, and particles remain suspended in the air,” Mahanta said.

IndiaSpend reached out to Arup Kumar Misra, chairman of the Pollution Control Board of Assam (PCBA). He said, “the air quality in Assam and more specifically, Guwahati, generally drops during the winter and pre-monsoon period due to lack of rainfall.” He added that Guwahati, being the largest city in the entire northeastern region, is also the main economic hub and has been going through a lot of infrastructural development. IndiaSpend also reached out to the Guwahati Municipal Corporation for comment. We will update the story when we receive a response.

Sources of Guwahati Air Pollution 

According to Roychowdhury, the main sources of air pollution are vehicles, open burning of waste, and construction activities. Apart from these, she said, in dumping grounds where methane emission happens from the rotting waste, if that catches a spontaneous fire, it tends to emit continuous toxic gases. She added that small and medium scale industrial units could also be a contributor.

Currently, the Guwahati Municipal Corporation dumps the city’s daily waste at Belortol in Paschim Boragaon village of Guwahati. The site is in close proximity to Deepor Beel--a freshwater wetland--listed as Assam’s only Ramsar site.

According to Shirshendu Sekhar Das, founder of Guwahati-based environmental conservation organisation The Midway Journey, “the dump site has been on fire for the last one month now. Due to high temperatures of the food and plastic waste, the harmful gases get ignited on their own. There is no fire extinguisher, it looks like it has been normalised.”

Parmod Kalita, a local conservationist, warned that the impact of the dumpsite near a Ramsar site is dangerous. “The plants in a wetland absorb almost 50% carbon dioxide, even more effectively than forests, so wetlands play a huge role in keeping the air quality intact of not just the nearby areas but perhaps the entire city. Deepor beel has been providing free ecosystem services and we don’t understand its importance.”

Smoke and pollutants from the dumping ground have been posing a threat to the ecology of the wetland, which is also home to migratory birds, and several other flora and fauna.

Arshel Akhter, an advocate for sustainable urban transportation, road safety and climate action, and also the co-founder of Pedal for Change in Guwahati, believes that a surplus of vehicles is a major contributor to air pollution in the city. “While there are other private constructions going on, we are witnessing more flyover-related construction work. We are making flyovers to accommodate more cars. It creates a phenomenon called ‘induced demand’ where people go on to buy more cars. Flyovers do not solve congestion. Road dust is mainly due to vehicles,” Akhter said.

According to the 1971 census, the population of Guwahati metropolitan area was just under 300,000 and in 2011, when India conducted its last census, it was estimated to be about 1 million. Anwaruddin Choudhury, a Guwahati-based environmentalist, said: “With the increase in population, the number of vehicles has also increased, which is causing pollution. The other reasons are dust from the construction sites and garbage burning, including plastic."

Over the years, several trees have also been cut down in the city. In 2023, the National Green Tribunal (NGT) had taken suo-motu cognisance of the allegations regarding the cutting of around 2,000 trees for a road expansion project between Guwahati and Goalpara in Assam. “Deforestation also has an impact on pollution--a lot of trees are being cut here and there for road widening projects. But some old trees could have been saved,” Choudhury said.

Guwahati Air Pollution: Health Impacts

According to Hyderabad-based Vishnun Rao Veerapaneni, consultant at the SWASA hospital on lung diseases for both children and adults, air pollution is a big threat to the entire human population particularly in big cities. “It affects all age groups. Outdoor pollution is mainly due to dust particles,” he said, adding that this PM 2.5 concentration which is rising in the Indian cities is especially dangerous because “it’s a big threat to all the organs, not only lungs but also heart, brain, and every cell of the body. This pollution is indirectly promoting the viral infections to contract. People who are exposed to pollution are easily getting targeted because lung linings are already damaged; therefore, viruses can enter easily into the lungs. Pollution and viral diseases go hand in hand,” Veerapaneni, who is also part of Doctors for Clean Air, said.

He added that PM 2.5 is “a kind of soot”. “The soot penetrates into the interiors of the lungs and reaches every cell of the body. It also indirectly causes strokes and heart attacks. It precipitates kidney problems.”

Guwahati Air Pollution: Urgent Need to Focus on Solutions

The Indian government’s National Clean Air Programme has identified 131 cities across the country as non-attainment cities, which means these cities have a higher pollution level and they are unable to meet the clean air standards. Guwahati is already among the 131 non-attainment cities and has been mandated to prepare and implement a clean air action plan.

The non-attainment cities are also mandated to prepare their emission inventory and conduct a source apportionment study to find out the key sources of pollution in the city and how much each of these sources are contributing to the overall pollution concentration.

However, a more accurate source for the pollution in Guwahati will be found out when the source apportionment study is completed. Currently, the study is being carried out by the PCBA along with the Indian Institute of Technology Guwahati (IIT-G), Misra told us.

Misra, the chairman of the PCBA, also said that the implementation of the city action plan under the National Clean Air Programme is ongoing. The major stake-holding departments include the transport, public works (road), Guwahati municipal corporation, PCBA, industries, forest, traffic. “The city action plan is based on specified six sources, which are construction and demolition activities, vehicular emission, road dust, industrial pollution, waste dumping, and burning and use of domestic fuel,” Misra said.

Roychowdhury of the CSE pointed out that in order to control vehicular pollution, public transport and electric vehicles need to be scaled up, and the emissions from the vehicles need to be monitored.

For waste management, she said, the municipality needs to ensure that the waste is collected from each and every household, and should be segregated as dry and wet waste. “The wet waste should be composted and not burnt, and the dry waste should be recycled; that’s how you can minimise the need to take the waste and dump it in the dumping ground,” Roychowdhury explained.

Das of Midway Journey said that “the municipality has taken some initiatives, as we are improving our waste collection services, but we must also ensure that the waste is collected in a segregated manner, which we have failed to do.”

Roychowdhury said that construction and demolition wastes need to be recycled. “The pollution control board has to ensure that [for] all these flyovers and road construction that is happening, they are adopting adequate dust control measures,” she added.

According to Akhter, “We need more monitoring stations, better transportation planning, more trees and a robust waste management system.”

Roychowdhury pointed out that the state pollution control board and the government should ensure that the clean city action plan gets implemented with “absolute stringency”.

This story was first published on IndiaSpend, a data-driven, public-interest journalism non-profit.

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