Earth Day: Road study puts air pollution blame on traffic indiscipline in Salt Lake
Telegraph | 17 April 2026
For years, cars have taken much of the blame for air pollution due to their emissions. But a study of 31 junctions across the city shows that seemingly innocuous factors — such as the mix of vehicles on the road and poor lane discipline — contribute significantly to the problem too.
“Developed countries have homogeneous traffic and strict lane discipline, but in India, cars, buses, trucks, rickshaws, e-rickshaws, cycles and even pedestrians often share the same road. Besides increasing the risk of accidents, this creates congestion, which is one of the main causes of air pollution,” says CK Block resident Parama Bannerji, assistant professor and head of the geography department at Naba Barrackpore Prafulla Chandra Mahavidyalaya.
Bannerji is also a guest lecturer at Rabindra Bharati University and, with students and faculty there, conducted this study on the impact of heterogeneous traffic movement on pollution. The same was published last week in the international academic publisher Springer.
“If traffic is homogeneous, vehicles can maintain a consistent speed, and car-following is predictable. But with heterogeneous traffic, a car moving at 60kph may suddenly find a rickshaw cutting into its lane. The driver is forced to brake sharply and crawl for the rest of the journey. Frequent braking and acceleration increase fuel consumption and hence pollution,” she explains.
Slow and polluted
Bannerji shares that in 2025, the average speed of four-wheelers in Calcutta was 17.4kph, compared to 50kph in urban areas of developed countries. They further identified four kinds of congestion on our streets.
The first, “simple interaction”, occurs when two vehicles come too close and are forced to slow down. “This is most commonly seen on MG Road, Shyambazar, Garden Reach and Kidderpore. This can happen due to mixed traffic or encroachment. In some places of Howrah, for instance, houses have even come up over drains, reducing road width,” says the lady who has a PhD in regional planning and has worked as an urban planner with Howrah Municipal Corporation.
The second type of congestion involves multiple vehicles bunching up and slowing down, as seen in Hazra, Ballygunge Phari and Maniktala. The third kind is where wide roads narrow into a bottleneck, such as at the Shyambazar five-point crossing. “The fourth is ‘network morphology’, with Ultadanga being a classic case. This is where traffic flows in from multiple directions,” she explains.
Dust bowls in Salt Lake
While the study focused on areas under the Kolkata Municipal Corporation, Bannerji believes it is Salt Lake and New Town that have a greater scope to implement its findings. “Calcutta is more than 300 years old, so altering its infrastructure is difficult. But newer townships still in the planning or development stage can incorporate such insights,” she says.
She appreciates the wider roads in New Town and its restriction on totos on main roads (they must use service lanes). “Many stretches also have dedicated cycle lanes and cycle docking stations. The issues there now are hawker encroachment, construction material spilling onto roads, and cars parked along the sides, all of which reduce motorable space and vehicle speed,” says the academic, who previously taught at Amity University, New Town.
For Salt Lake, she recommends urgent road repairs. “There are numerous potholes, especially in interior lanes. Not only do these slow down vehicles, but their loose stone chips and broken surfaces create dust. Every passing car kicks up particles, significantly worsening air pollution,” she says. The dust situation is particularly severe in blocks like CL, that face Metro construction,” she says.
The authorities could sprinkle water on roads to reduce dust, Bannerji says. “And instead of patchwork on broken roads, interlocking concrete topped with bitumen could be used. Slow-moving vehicles like e-rickshaws should be banned from main roads, and public transport must be subsidised so more people use it. All developed countries have highly efficient public transport systems,” says Bannerji, who herself commutes by an electric car.