Record air pollution keeps choking Dhaka

Infographic: TBS

Dhaka has suffered from record levels of air pollution in recent weeks, often topping lists of the most polluted cities on the planet.

With an Air Quality Index (AQI) score of 297 at 8:50am Thursday, the populous city again ranked first on the list of cities with the worst air, which is in the "very unhealthy" category – very close to becoming "hazardous".

The AQI, an index for reporting daily air quality, informs people how clean or polluted the air of a certain city is and what associated health effects might be a concern for them.

The Centre for Atmospheric Pollution Studies (CAPS) at Stamford University has been conducting regular assessments of Dhaka's air quality for the past seven years and providing data for the AQI index, maintained by the US Environmental Protection Agency. 

An AQI score from 0 to 50 is considered "good", 51 to 100 is "moderate", and 101 to 150 is "unhealthy for sensitive groups".

When the score stands between 151 and 200, it is considered "unhealthy", 201–300 is ''very unhealthy", and 301 and higher is "hazardous", which poses severe health risks to residents.

Iraq's Baghdad and Myanmar's Yangon occupied the second and third places with AQI of 238 and 193, respectively.

According to CAPS data, in January and February of 2013, Dhaka saw a total of 13 days with "hazardous" air quality, which is the highest in seven years. 

Of the 13 days, 10 were marked in January and three in February with AQI scores above 300. On 13 January, the city got the highest AQI score of 404. 

On the other hand, the number of days with hazardous air quality counted was five in 2017, six in 2018, six in 2019, seven in 2020, 12 in 2021 and five in 2022.

The number of days with "very unhealthy" air quality counted was 64 in 2017, 79 in 2018, 60 in 2019, 69 in 2020, 87 in 2021, and 77 in 2022. 

In January 2023, 20 days were marked as having very unhealthy air conditions.

According to CAPS data, air pollution in Dhaka increased by about 27% in January 2023 compared to last year. In January 2022, Dhaka's average AQI was 221, which stood at 281 in 2023.

The average AQI score was 226 in February 2023. Although pollution in February decreased slightly compared to January, it was still high when compared to the previous years' data.

The AQI in Bangladesh is based on five pollutants: particulate matter (PM10 and PM2.5), NO2, CO, SO2, and ozone.

Dhaka has long been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon, but mostly remains in the unhealthy category.

Although winter has subsided, the air quality in the capital did not see much improvement in February, which saw eight "unhealthy" days and 15 "very unhealthy" days, not to mention the three "hazardous" days.

Dr Ahmad Kamruzzaman Majumder, founder and chairman of CAPS, told The Business Standard (TBS), "Air pollution is increasing in Dhaka due to ongoing development work and uncontrolled road digging. Waste burning has also become a major source of air pollution, which is gradually taking the city's air from harmful to very harmful levels."

Air pollution has long been recognised as a risk factor for developing heart disease, chronic respiratory diseases, lung infections and cancer, according to several studies.

According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, mainly due to increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections.

Mohammad Golam Sarwar, an environmentalist and assistant professor at the Department of Law at the University of Dhaka, told TBS that the Department of Environment needs to be at the forefront of preventing all forms of pollution as Bangladesh moves to achieve the status of a middle-income country. 

"I do not think the Department of Environment is prioritising the pollution issue at all. It is reluctant to follow the instructions of the High Court. Besides, the department's capacity should be increased," the environmentalist said.

"The main sources of air pollution are vehicles that have no fitness and brickfields. Air pollution is killing city dwellers. Average life expectancy is decreasing, which is directly depriving us of our fundamental rights," Golam Sarwar added. 

According to a 2022 study by the World Bank, about 40% of pollution in Dhaka's air is due to natural causes and human actions taking place within the city. But 28% of the pollution is regional, especially of Indian origin. And the rest, 60% of the pollution, originates from adjacent divisions and districts.

The study also mentioned multiple pollutants, mostly dust, dirt, soot, smoke, fumes, and liquid droplets and sources of these pollutants, which include automobiles, power plants, factories, brickfields, unpaved roads, and construction sites.