Manufacturing and construction, meanwhile, account for 58 per cent of the city’s planet-warming emissions, showed an assessment by the South Asia branch of ICLEI – Local Governments for Sustainability, an international body that helps cities with green policies.
Major sources of pollution include the city’s seven cement factories, 70 to 80 illegal brick kilns and a number of steel mills, said Moinul Islam, town planner for Narayanganj City Corporation.
Narayanganj Mayor Selina Hayat Ivy, the first woman to head a city corporation in Bangladesh, told the Thomson Reuters Foundation she had asked cement and lime factories to relocate away from residential neighbourhoods.
In April, the city corporation approved an action plan for low-carbon, climate-resilient development, supported by ICLEI, making Narayanganj the first Bangladeshi city to adopt such a plan, said Jubaer Rashid, Bangladesh representative for ICLEI South Asia.
“We assessed the vulnerability of the climate-impacted urban systems like energy, water supply, waste management and so on, and came up with realistic recommendations for the city to implement,” he said.
The city administration has already set up air-quality monitoring systems with help from ICLEI to detect and measure polluting gases like carbon monoxide, nitrogen dioxide and sulphur dioxide, as well as particulate matter, with real-time data displayed on public screens.
ICLEI has also encouraged renewable energy adoption in the city and has set up rooftop solar power systems at some public facilities including a public library and a hospital.
But cities have limited authority over policies and actions to tackle climate change in Bangladesh, where central government agencies are charged with delivering public services nationwide.
Municipalities need backing from central government to roll out their plans, said Rafiur Rabbi, leader of the Citizens’ Committee, a local movement working on social and environmental issues.
The Department of Environment, for instance, enforces regulations on emissions and effluent management, while district deputy commissioners allocate land to factories.
Narayanganj industrialised rapidly in the last 100 years owing to its strategic location on the 113 km-long Shitalakhya River, which meets the Dhaleshwari River near the city, according to local journalist Golam Rabbani.
Jute, hosiery and garment industries developed in the city as the goods could be transported along the Shitalakhya.
In addition, Narayanganj has more than two dozen canals for water transport and stormwater drainage to prevent flooding.
But in recent decades, there has been sustained encroachment on the river and canals, hampering run-off of stormwater and causing water-logging in some areas, said activist Rabbi.
The city corporation has been working to restore 26 canals in phases, which is expected to stop bad odours, boost vegetation and enable inhabitants to get around more easily.
“Water bodies also reduce the heat island effects in urban areas through evaporation,” said environmental engineer Dipak Bhowmick, ICLEI’s project officer in Narayanganj.
The Shitalakhya, however, has been damaged by dumping of untreated industrial effluents and municipal waste in its water, decimating biodiversity and making it “biologically almost dead”, said journalist Rabbani.
This has hurt local people too. Manoranjan Goswami, 73, a leader of the fisher community in eastern Narayanganj, lamented the loss of fish and erosion of traditional livelihoods.
“There are around 100 fisherman families here, but the fish stock in the river is mostly gone,” he said.
Smaller businesses usually lack funding to install and operate effluent treatment plants, said activist Rabbi, urging the government to set up central treatment plants to serve industry clusters.
The city corporation is working to build eco-parks - ecological zones including forests, wetlands and recreational green spaces - along the banks of the main river and canals to protect water bodies and address climate change, said Mayor Ivy.
Reducing river and canal pollution could also help ease growing pressure on underground aquifers as residents sink tube wells to extract clean water for their own use, she added.
Mohammad Babul Hossain, 60, moved to the city from Chandpur several years ago, and has worked as a taxi and rickshaw driver in Narayanganj - a place he prefers as “there is too much hurly-burly and trouble over there in Dhaka”.
At least three-quarters of Narayanganj’s roughly 2.5 million-strong population are migrants from across Bangladesh.
As one of the most vulnerable countries to climate change, Bangladesh could see its internal climate migrants top 13 million by 2050, according to a 2018 World Bank report.
Boatmen like Mansur Gazi, 48, and Mahadeb, 45, who also left their flood-prone riverine district of Chandpur for Narayanganj, ferry people across the Shitalakhya for a few cents a journey.
Most of the manual and electric rickshaws that serve as popular transport in the city are also driven by migrants.
But their presence can cause social tensions, as “newcomers often settle down as roadside hawkers, causing congestion”, noted Rabbi.
Despite growing migration, Narayanganj - like the vast majority of cities - lacks a formal strategy to deal with the challenges, while migration as a way of adapting to climate change pressures is not included in its ICLEI-backed climate action plan.
Insufficient finance is the key constraint to Narayanganj’s efforts to pursue a climate-smart development model, said Mayor Ivy.
The city corporation’s annual budget for 2021-22 is about $80 million, while in Rajshahi - which has less than half the population but is the main city of its administrative division northwest of Dhaka - it is more than $120 million.
“We need a larger budget,” said Ivy, noting Narayanganj’s outsized contribution to the national economy.
ICLEI is working closely with the city corporation to formulate project proposals that include climate concerns and pitch them to global development organisations for funding, said ICLEI South Asia project officer Bhowmick.
The World Bank, Japanese government and Asian Development Bank are among those that have funded projects in the city.
Town planner Islam urged other government organisations working there, such as the Department of Environment and the Bangladesh Inland Water Transport Authority, to coordinate their activities with the city’s sustainable development aims.
ICLEI country head Rashid said Narayanganj would serve as a pilot for low-emissions urban development in Bangladesh. Rajshahi is the second city to approve and start implementing a climate action plan, but there are no others as yet, he noted.
The southwestern port city of Mongla, meanwhile, has made some progress, with Bangladeshi organisations helping it craft a strategy for infrastructure to prevent flooding, as well as opportunities for climate migrants.
“The example of Narayanganj will demonstrate how local governments could play a role in realising the goals of the Paris Agreement on climate change,” Rashid said.