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According to the World Air Quality Report for 2024, published by IQAir, a Swiss company that monitors global air pollution levels, Byrnihat, a town on the Meghalaya-Assam border, has been declared the most polluted city in the world.
The report states that the annual average concentration of PM2.5 in Byrnihat was 128.2 micrograms per cubic meter (µg/m3), which is alarmingly high compared to the World Health Organization’s (WHO) annual air quality guideline of just 5 µg/m3.
This is not the first time Byrnihat’s air quality has made headlines. In January 2024, the Helsinki-based Centre for Research on Energy and Clean Air also ranked Byrnihat as the most polluted city in India based on monthly average PM2.5 levels.
The news has raised an important question: how did this small town, surrounded by scenic landscapes, become a pollution hotspot?
Industrial Boom and Its Consequences
Byrnihat is located about 20 km from Guwahati and 65 km from Shillong, within Meghalaya’s Ri-Bhoi district. Over the years, it has transformed into a major industrial hub due to its strategic location where the hills of Meghalaya descend into the plains of Assam.
While the residential parts of Byrnihat are in Meghalaya, the industrial zones extend into both Meghalaya and Assam. In Meghalaya, the industries are concentrated in the Byrnihat Export Promotion Industrial Park (EPIP), while in Assam, they are situated in Tamulikuchi in the Kamrup Metropolitan district, along the national highway passing through the town.
The town houses industries producing coke (fuel), cement, ferro alloys, steel, and bricks, as well as distilleries. These industries emerged in the region primarily due to the easy availability of coal from Meghalaya, the proximity to the major urban center of Guwahati, and access to water from the Umtru River.
According to the Meghalaya State Action Plan for Prevention and Control of Air Pollution, released in December 2024, Byrnihat has 39 industrial units in Assam and 41 in Meghalaya.
Out of these, 20 industries in Assam and five in Meghalaya fall under the “red category” — a classification by the Union Ministry of Environment and Forests that identifies industries causing heavy pollution. These include cement factories, distilleries, iron and steel plants, and coke production units.
Additionally, 15 industries in Assam and 22 in Meghalaya are classified as “orange category” industries, which include brick manufacturing and cement clinker grinding units.
Failure to Follow Environmental Norms
Despite the severe pollution levels, many industries in Byrnihat are failing to comply with environmental regulations.
Meghalaya Chief Minister Conrad Sangma informed the state legislative assembly that surprise inspections were conducted in industrial areas in late January and early February. Following these checks, the Meghalaya State Pollution Control Board issued closure notices to seven industrial units and imposed environmental penalties on two others.
The violations included “heavy emissions from chimneys due to non-operation of pollution control devices, ineffective pollution control devices, and non-transmission of online emission data,” the Chief Minister stated.
Similarly, Assam Pollution Control Board chairman Arup Kumar Misra acknowledged that many industries in the region are not adhering to pollution control regulations.
“There are industries there which are not following the rules… Many have the required devices which can trap pollutants but don’t use them because those are energy intensive and incur costs,” Misra told The Indian Express.
Vehicular Pollution and Geographical Factors
Apart from industrial emissions, vehicular pollution is another major contributor to Byrnihat’s poor air quality.
Dr. Ganesh Chandra Dhal from NIT Meghalaya, who has conducted research on air pollution in the region, pointed out the significant role of traffic emissions.
“This is an important transit point for vehicles. Material is loaded and unloaded from heavy diesel vehicles, many of which do not comply with tailpipe emission norms. Vehicles idle in congestion on the road. Besides PM2.5 and PM10, sulphur dioxide levels are also high in the area,” he said.
A study by a CSIR-NEERI team in 2022-23 also found that unpaved roads in Byrnihat worsen air quality by increasing road dust levels.
Moreover, the town’s geographical location plays a crucial role in trapping pollutants. Experts have described Byrnihat’s topography as “bowl-like,” which prevents the dispersion of air pollutants.
Dr. Rajesh Bajpai, an environmental studies professor at North-Eastern Hill University, explained, “It is like a basin. While there are hills and high elevation on either side, the area itself has an altitude of only about 60 meters. It experiences a valley-and-basin effect, because of which wind speed is reduced. This may be impacting the transport of air out of here.”
The Urgent Need for Action
Byrnihat’s air pollution crisis is a wake-up call for policymakers and environmental authorities. While the town’s industrial growth has contributed to economic development, it has come at a severe environmental cost.
Stronger enforcement of pollution control measures, investment in cleaner industrial technologies, stricter vehicle emission norms, and better urban planning are essential to reversing the air quality crisis. Without immediate intervention, Byrnihat may continue to hold the unwanted title of the world’s most polluted city, posing severe health risks to its residents and the surrounding region.
