Dhaka's air turns toxic again, index hits 186 in Agargaon
After last week's heatwave, temperatures across the country have begun to fall, and the capital Dhaka is also feeling a touch of winter. But there is no improvement in the air. As in most of the year outside the monsoon, Dhaka's air was unhealthy on Saturday too.
On the index of the Switzerland-based organisation IQAir, Dhaka ranked third among the world's most polluted cities on Saturday evening. Kuwait City and Kolkata held the first two places. At that time Dhaka's air quality index was 164, which is considered 'unhealthy'.
Pollution from many sources, including dust from construction work and black smoke from vehicles, has kept Dhaka near the top of the list of the world's polluted cities for many years. Even the capital's upscale neighbourhoods are not spared.
Several places in Gulshan, Banani, Baridhara and Dhanmondi, as well as Pragati Sarani, have recently appeared among Dhaka's 10 most polluted monitoring stations.
On IQAir's index, the highest pollution among Dhaka's monitoring stations on Saturday evening was recorded near the Bangladesh Institute of Development Studies (BIDS) in Agargaon, where the air quality index was 186.
Baridhara Park Road came second with a score of 168. Pragati Sarani in Badda and Becharam Dewri recorded 167, followed by Baridhara Lakeside and Dhanmondi at 161, Gulshan Lake Park at 160, Eastern Housing in Banani at 156 and the Grace International School area in Gulshan 2 at 151. The air at every one of these places was at the 'unhealthy' level.
On the air quality index, a score of zero to 50 is considered 'good', 51 to 100 'moderate' and 101 to 150 'unhealthy for sensitive groups'. A score of 151 to 200 is 'unhealthy', 201 to 300 'very unhealthy' and above 300 'hazardous'. By that measure, the air in the capital's upscale areas mentioned is also at the unhealthy level.
Experts say these areas are among the most attractive in Dhaka for housing and business. But without clean air, they could lose their appeal to residents in future.
Experts say that alongside local activity, pollution from surrounding areas also contributes to the air pollution in Gulshan, Banani and Dhanmondi. Smoke from cooking on clay stoves and burning waste in the Korail slum can reach Gulshan and Banani, while pollution from Kamrangirchar can spread as far as Dhanmondi. Similarly, dust from digging along Pragati Sarani may be worsening Baridhara's air pollution, they believe.
Professor Dr Ahmad Kamruzzaman Majumder, dean of the Faculty of Science and professor of environmental science at Stamford University Bangladesh, said several geographical and environmental factors keep air pollution persistent in the upscale lakeside areas. Because the air above water bodies holds more moisture and water vapour, dust and smoke particles (PM2.5 and PM10) cannot float away easily; instead they combine with the vapour, grow heavier and remain suspended in the air. In winter, temperature inversion also creates a layer of cold air near the lake below and warm air above, like a lid. As a result, vehicle smoke and dust cannot rise and instead accumulate below.
Associate Professor Dr Mohammad Enayet Hossain of the Department of Soil, Water and Environment at the University of Dhaka said the role of high-rise buildings in the geography of Gulshan and Banani is extremely important for air pollution. He said the tall buildings standing side by side block the natural path of airflow, a phenomenon known in science as the urban canyon effect. When the air is excessively humid and smoke comes from nearby vehicles and slum areas, these tall buildings prevent the wind from carrying it away. As a result, the polluted particles stay trapped in the air close to the ground, multiplying local air pollution many times over.
Those concerned believe that if pollution continues, even these upscale areas will lose their appeal, and they demand that the government improve Dhaka's environmental quality at any cost. Gulshan Society president Barrister Omar Sadat blamed the smoke from private cars for the air pollution in areas like Gulshan and Banani. He said: "We can stop everything, but we cannot stop the air. As people of Bangladesh, we are accepting this pollution. But as a result, our lifespan is shortening. Pollution can be reduced if action is taken against unfit vehicles. And to do that, corruption in the BRTA must be reduced. So many unfit vehicles emitting black smoke are running in Dhaka. So this is the first thing to think about in controlling air pollution."
Alongside vehicle smoke, ongoing construction work is also spreading pollution in these areas, those concerned believe. In their view, the air nearby is being polluted because the necessary protective measures are not taken to stop dust from construction sites from spreading, even though the law requires such measures and they are not properly enforced in practice.
Banani Society president Shawkat Ali Bhuiyan (Dilon) said a great deal of construction work is going on in Gulshan and Banani. Abroad, such work involves several layers of protective measures. In our country the law has them too, but they are not properly enforced. The Korail slum also plays a role in the surrounding pollution. Good hospitals and clean markets must be arranged to ensure a decent life for its residents. The two city corporations must also follow the correct guidelines on burning waste. With a coordinated effort, Gulshan, Banani, Dhanmondi and the whole of Dhaka can be kept free of air pollution.
On the overall issue, Siddhartha Shankar Kundu, deputy secretary (environmental pollution control-1) at the Ministry of Environment, said regular activities to control air pollution are continuing and a committee exists on the matter. The committee's upcoming meeting will discuss the issue in detail and decide the next policy and course of action.
