Just over a decade ago, in 2008, almost half of the world's total population used to live in urban areas. This phenomenon has continued and is expected to gain further momentum in future. According to United Nations (UN), it is projected that the world urban population will increase by 72 percent by 2050, from 3.6 billion in 2011 to 6.3 billion in 2050 of which the majority of the population will be concentrated in the urban areas of the less developed regions.
Cities such as London or New York in developed countries have had very slow growth between 1970 and 2011, compared with cities in the developing world. India, for example, already has three megacities (Delhi, Mumbai and Kolkata) and with the addition of Bangalore, Chennai and Hyderabad, India is expected to have six by 2020. The country will have the largest concentration of megacities in the world. This gives one an idea of the pressure of population growth in cities of developing countries.
WHAT IS A 'MEGACITY'?
The concept of megacity evolved at the end of the twentieth century to describe the large urban agglomerations of the world. Few inconsistencies exist in literature regarding the population threshold used to define a megacity. For example, Mitchell defines a megacity as having a population exceeding one million, whilst others have used a five million or an eight million population threshold. Most concrete definition is given by the UN (2003): a megacity is a conurbation that houses ten million people or more; which is widely accepted nowadays.
THE GLOBAL PHENOMENON OF URBANISATION
In the 1970s, there were only two megacities with a population of more than ten million. At present, 9.9 percent of the world urban population lives in 23 megacities. The number is projected to increase to 37 in 2025 when they are expected to accommodate 13.6 percent of the world urban population. The number of people living in megacities has increased almost tenfold in the past 40 years, from 39.5 million in 1970 to 359.4 million in 2011, and could double again by 2025 (UN 2012). Interestingly, the largest increase in urban population between now and 2050 is expected to be concentrated in Asia and Africa.
WHERE DOES DHAKA LIE?
Even though Bangladesh has achieved an amazing feat in reducing the annual growth rate of population, the size of population is still large when compared with the size of the country. If the current trend continues, the population of Bangladesh is expected to reach about 194 million in 2050 (UN 2012). Understandably, this population exerts tremendous pressure on a limited resource base. As a result, both landlessness and environmental degradation have become rampant in recent times. For instance, the total proportion of land holdings being farmed has been reduced from 72.7 percent in 1983 to about 58.6 percent in 2008. Furthermore, because of rapid growth of urbanisation and associated infrastructure, every year Bangladesh loses 0.3 percent of its cultivated land. We have to keep in mind that the economy of Bangladesh is still mostly agrarian with 48 percent of the labour force engaged in agriculture and related activities (BBS 2010).
Along with national population growth, the percentage of people living in urban areas has also been rising. 1.8 million people were living in urban areas in 1951 which increased to 13.5 million, 22.5 million, 31 million and 33.5 million in 1981, 1991, 2001 and 2011 respectively; an eighteen-fold increase in the last 60 years. This astonishing growth in urban population is largely attributed to three main factors, namely: (i) rural-urban migration, (ii) natural growth and (iii) the redefinition of urban areas. It is affirmed by experts that among them, rural-urban migration is the most dominant factor. Moreover, the country faces enormous challenges in coping with the infrastructures and service requirements for its rapidly growing urban population, particularly in the capital city Dhaka.
Dhaka has seen astonishing growth and rapid development since 1971. It has changed into the capital of a nation from a mere provincial city since the birth of Bangladesh. It is one of the only seven cities in the world which has experienced urban population growth higher than 2.4 percent between 1975 and 2005 (UN 2006). It was one of the top ten megacities in the world in 2011. Unfortunately, the development took place in an unplanned way, especially since the 1990s. These days the name Dhaka regularly comes up in the list of the most unliveable cities.
A CITY BURDENED WITH TOO MANY PEOPLE
The capital city Dhaka has extensive administrative and infrastructure facilities, as well as extensive road and telecommunication networks, which are definitely better than any other cities of the country. Hence, it has become the focus of urban expansion and the hub of all economic activities. For obvious reasons, marginalised rural people are attracted to the area and come here in the hope of better employment opportunities and an improved lifestyle. As a result, it has become one of the fastest growing cities in the world, primarily driven by staggering population growth. The population of the city was a mere 0.41 million and 0.71 million in 1951 and 1961 respectively. By 1974, it had risen to 2.06 million, with an average annual growth rate of 11.15 percent (BBS 2008). In 1981, the population increased to 3.44 million and reached around 6.48 million and 9.67 million by 1991 and 2001 respectively (BBS 2001, 2003).
Currently, the megacity's population is more than 14 million, with an average annual growth rate of 4.08 percent between 1991 and 2001, outpacing the country's annual growth rate of 1.3 percent with a distant margin. If the current rate of population growth continues, Dhaka will exceed Beijing in size by 2025, with a projected population of 22.9 million (UN 2012).
As stated before, research studies indicate that the rapid growth of the urban population is mainly driven by rural-urban migration. Islam (1991) reported that more than 60 percent of people in Dhaka are migrants. A study in the recent past shows that Dhaka receives 300,000–400,000 migrants every year (Sanderson 2012). Studies have also shown that rural-urban migration is age-selective; more and more youth are pouring into the city from all parts of the country.
A TRANSPORT SYSTEM IN DIRE STRAITS
Dhaka suffers from traffic congestion, which is deteriorating, despite its low level of motorisation. This horrible situation prevails largely due to absolute lack of roads, deficient road network configuration and inefficient traffic management. The existing public transport system, bus transit operations in particular, is characterised as far short of the desirable mobility needs of the people in terms of reliability, comfort, speed and safety. In Dhaka, buses are generally considered unreliable and time-consuming to reach one's destination. It is one of the very few megacities in the world without a proper public transport system.
The present public transport system in Dhaka city consists of only conventional bus services (buses and minibuses) and para-transits (e.g. rickshaws, auto-rickshaws, taxis, battery bikes, etc.). Lack of effective public transport system and preference of door-to-door services influence the augmentation of private cars and other forms of transport. The railway was very popular and still is a relatively safer and cheaper transport system in Bangladesh; as a consequence of the absence of proper initiatives and investment in the urban corridors, it could not play the expected role in Dhaka's public transport system. Moreover, rail tracks run through the Central Business Districts (CBDs) and congested areas of the city with numerous level crossings which result in enormous congestion.
All these factors have created a situation where cars and motorcycles are increasingly becoming a necessity for the middle class to get around in Dhaka. As a result, there is further congestion in roads and worsening air and noise pollution and safety issues.
The number of registered motorised vehicles stands at 1,255,402 as of April 2018, an increase from 303,215 in 2003 (a fourfold increase in 15 years). More than 36 percent of all registered vehicles are in Dhaka (a total of 3,419,884 in Bangladesh) (BRTA 2012, 2018).
During this period the percentage of buses and minibuses has remained almost the same; private vehicles, particularly the number of cars and motorcycles, have almost tripled. Public transport such as buses and minibuses has grown at a very insignificant rate even though the demand for public transport services is increasing. Motorcycles and cars constitute around 54 percent and 26 percent of total motorised vehicles respectively.
To improve the current situation and reorganise the existing traffic system methodically, the government prepared the Strategic Transport Plan (STP) for Dhaka (2005) which has been recently revised (it has now become Revised Strategic Transport Plan, RSTP since 2015). It recommended a package of comprehensive programmes for the development of transport infrastructure over a 20-year period. This strategy includes various types of development agendas, such as three Bus Rapid Transit (BRT) and Mass Rapid Transit (MRT) (Metrorail) routes, more than 50 highway projects, expressways, flyovers, etc.
But unfortunately, the implementation of the components of STP or RSTP does not reflect the intention to mitigate transport problems of the masses. Ignoring the needs of non-motorised travellers and pedestrians, recent policies at all levels of the decision-making processes have focused mostly on trying to lessen the travel time for the motorised elite of the city by putting preference on the construction of numerous grade-separated flyovers, overpasses and interchanges (e.g. Jatrabari-Gulistan flyover, Kuril interchange, Banani overpass, expressways, etc).
The rapid motorisation and heavy infrastructural development which promote cars come with the depletion of transportation equity in a city. For example, from an environmental and equity perspective, major concerns exist regarding the unwanted increase of motorised two-wheelers. Some have even characterised the motorcycle as likely the “most challenging” transport problem that Asia will face in the next decade. The rise of private transport and current prevalence of NMT (Non Motorised Traffic, mostly rickshaws) are not a sustainable solution although they may help to increase mobility in the short term. Already authorities tried to and have been successful in banning NMT from some parts of the city. So, like other developing cities around the world, NMT will be restricted in near future for Dhaka too. Hence, for transportation equity and accessibility, not only is public transit necessary but so is MRT (e.g. subway, BRT, LRT etc) and we hope that the ongoing projects of MRT and BRT will help ease the present horrendous situation.
CHOKED TO DEATH BY AIR POLLUTION
Dhaka has been historically infamous for being heavily polluted. It was termed as the most polluted city when the presence of lead (Pb) in the air was reported to be higher than in the atmosphere of any other place in the world back in 1997. Pollution from traffic and brick kilns has been identified as two of the most significant factors by studies. In the late 1990s and early 2000s, in order to improve the severe situation, the authorities took some important decisions (e.g. banning two-stroke engines, introducing Compressed Natural Gas (CNG), etc). But other than numerous sporadic studies and projects, there has been little systematic research or successful project implementation on air pollution in the city. Unless the situation becomes extremely hazardous or almost uninhabitable, what the authorities usually do is adopt the “do nothing” approach.
The main culprits for air pollution are large numbers of high-polluting vehicles, impure fuel, inefficient land use, overall poor traffic management, and industries (especially brick kilns). The most important pollutants have been identified as carbon monoxide, sulfur dioxide, lead, nitrogen oxides, ozone, hydrocarbons, suspended particulate matter and last but not least, particulate matter with an aerodynamic diameter of less than or equal to 10µm (PM10 and PM2.5). Observations show that the concentration of sulfur dioxide, ozone, carbon monoxide and nitrogen oxides goes up in the dry season significantly. The same is true for PM2.5 and PM10.
The estimated PM emissions from different modes indicate that around 54 percent emission contribution is from buses/minibuses, followed by trucks and tankers (26 percent). The black spot areas for PM were located in the intercity routes and the major bus terminals. The bus terminals (Gabtoli and Sayedabad) showed average estimated values above 110 μg/m3 of PM. Locations with highest concentrations of PM are Sheraton, Farmgate, Sonargaon, Mohakhali-Gulshan intersection and Banglamotor.
When a team of researchers performed field studies in the 90s, to measure ambient NO2 concentration in 51 street locations, one residential area and four personal exposures, 35 of them were identified as black spots. Most polluted locations of nitrogen oxides were Sayedabad bus stand, Sheraton hotel roundabout, Sonargaon hotel roundabout, Farmgate intersection and Moghbazar intersection. The calculation of nitrogen oxides indicated that buses and minibuses (diesel operated) and motor cars have a significant contribution of nitrogen oxides (30 percent), followed by heavy-duty vehicles (trucks and tankers) (28 percent). The situation has gotten much worse now after 20 years, as there have been no visible steps to improve the situation.
Researchers found that nitrogen oxide and sulfur oxide emissions from transportation systems in national pollution averaged 34 percent and 47 percent, respectively. In case of sulfur dioxide in Dhaka, the contribution mainly comes from high sulfur content in the diesel fuel. It was estimated that buses powered by diesel fuel contribute 58 percent sulfur dioxide emission followed by trucks and tankers at 34 percent.
At present, air pollution in metropolitan Dhaka has been increasing at a steady rate for more than three decades. Annual average increases of 6.5 percent in nitrogen oxides, 5.8 percent in hydrocarbons, 5.9 percent in carbon monoxide, 5.6% in PM and 6 percent in sulfur oxide emissions were observed from 1981 to 1996. These rates have certainly not gone down, as the number of motorised vehicles is rapidly increasing, which results in chronic congestion almost at every intersection, resulting in more and more emissions.
It is proven that the impact of policy decisions (e.g. banning of two-stroke engines and leaded gasoline, introduction of CNG, etc.) can have far-reaching effects in a positive way. The ever-increasing amount of PM2.5 and PM10 is getting out of hand, and making the city one of the most polluted in the world. If we do not take proper effective measures to mitigate the problem now, we will face grave consequences.
Dhaka is probably one of the very few megacities in the world without any properly planned design or guideline for expansion of the mass transit system. There are few others like us such as Lagos, Karachi and Kinshasa, but none of them has a population density of about 50,000 people per square kilometre. According to some projections, approximately 24 million and 35 million people will reside in Dhaka by 2030 and 2050 respectively. So, if Dhaka is to survive the juggernaut called “development” and “urbanisation”, it must have a proper plan not only to provide guidelines on paper but also for implementation in reality—and there is little scope for mistakes.
Dhrubo Alam is Technical Consultant (Transport), Dhaka Metro Preparatory Technical Assistance Project, Dhaka Transport Coordination Authority. Email: firstname.lastname@example.org
Significant portions of the article were inspired by the book Dhaka Megacity: Geospatial Perspectives on Urbanisation, Environment and Health by Robert J Corner and Ashraf M Dewan. The author would like to express his gratitude to and is indebted to Professor Dr Mazharul Hoque (Professor, BUET, retired) for his expert comments and opinions.