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25 May, 2017 00:00 00 AM

Ensuring environmental security for sustainable urbanisation

Increase in urban population has created a tremendous pressure on the existing network of intra-urban and inter-urban roads and highways as both the number and the volume of vehicular of traffic increases within the city
Ensuring environmental security for 
sustainable urbanisation

The swiftness of urbanization had been rapid in the twentieth century. At the beginning of the twentieth century, only one tenth of the world population lived in cities and at its end, over half of its population was living in urban areas. In the developed countries, growth of urban population has stabilized. In developing countries, urbanization is taking place at a rapid pace. UN source states that by 2025, about 80% of urban population of the world will live in the developing countries. 

Dhaka has a population 14.4 million and density of 19,447 people per square miles. Dhaka density stands at an astounding 49,182 per sq. km and Chittagong 16,613 sq. km. Economic and Social Affairs, Population Division of UN, 2016 has mentioned the urban Population Status in Bangladesh: it was 23.8% in 2000; 30.4 % in 2010 and 2016 it is now 34.9%. It can be 38% of the total population by the year of 2020. Economically affected, socially excluded and environmentally displaced people will join in urban area as beggar, hotel worker, porters, day laborers, maid servant, rickshaw puller, petty traders etc. It has been estimated that urban population in Bangladesh will rise to between 91 and 102 million by 2050 which will be 44% of total population. 
In urbanization, all processes are viewed in relation to the city. In general, better food supply, good medical care, education, jobs, industrialization, commercialization, electrification, specialization of professions and entertainment are the basic causes of urban growth. Accessible energy plays an important role in our development, with this people can enjoy all the modern facilities. By establishing road communication, an undeveloped area may be connected with a developed area. It helps the people of the areas, information technology and use of media for improved education and information. 
Urbanization does not bring only good fortune to our society, also it bears demerits − population explosion, movement of people from rural to urban, increasing environmental pollution, farmers losing their farms, cutting down forests, global warming, and disruption of ecological systems. In urban area, issues on public transportation, low-cost housing, urban health, slum improvements also included. Apart from that, some problems are crucial for urban poor. Greater reliance on cash economy, livelihood in informal sector, overcrowded living condition, frequent shift of residence, environmental hazards, social fragments, exposure to crime, violence and accidents. 
There are over 3500 slums in the metropolis of Dhaka having a population of more than 5 million. In Chittagong, there are more than 1500 slums housing more than 7, 50,000 people. Not only are these squatter settlements a reflection of urban poverty but they are also contribute to the deteriorating law and order situation of the cities. Urban poor, people who are living slums, squatter and low income settlements. The top income class of only 5.4% of households but they enjoy 39.9% of all Dhaka’s income. In contrast, the bottom 58.4% of households enjoys an income share of only 21% (PPRC, 2017). 
Survey around 6000 households (UNICEF Report, 2015) implies, in urban poor areas among the latrines, pit latrine with slab without lid and water-seal is the major one -53%. Pit latrine with slab and water-seal is 13%. Pit latrine with slab without water-seal is 5.9%. Pit latrine with slab and flap without water-seal is 8.1%. Latrine without slab or open pit latrine is 7.3%. Latrine connected with open drain with flush or pouring water is 5 %. Flush latrine connected to septic tank is 3.1%.  Use of hanging latrines is 3.1%. Pit latrine with ventilation system 1.4%. Dhaka- which has piped sewage network, 2% only of fecal load is treated.    
Asian water development outlook, 2016 mentions; 80% wastes are dumping into river in Bangladesh. Water security index indicates Bangladesh is 44th out of 48 countries. Around 250 industries are discharging chemical pollutants into Buriganga and Sitalakka River. Every day four thousand tons solid waste & 22 thousand tons tannery waste mixes with water in Buriganga River. Different industries and their contribution to pollution in Dhaka are: Pulp & paper - 47.4%; pharmaceuticals - 15.9%; Metals - 14%; Food industry - 12.1%; Fertilizers/pesticides - 6.6%. In urban areas, sewages are discharging directly into the rivers and low-lying part around the urban areas. 
Wetlands around the Dhaka city are being destroyed through land development and dumping of toxic effluents and untreated sewage. In Bangladesh, cities have sprung up alone the banks of different rivers. Industrial effluents have totally destroyed the biota in the rivers near these large urban areas. In Dhaka, 20 canals have lost her life out of 42. Liquid, solid wastes and heavy metals − copper, iron, lead, nickel is distressing the BOD, COD, DO, TDS, PH of water.
For any urbanized country, incidences of air pollution are far more widespread in the urban areas than in the rural areas. In Bangladesh, the level of air pollution is highest in Dhaka followed by Chittagong and Khulna, the two other industrial cities. Incidence of air pollution is not an isolated event but is a continuous process as the sources of pollution operate throughout the year. The concentration of CO, NOx, PM10 and CO2 in Mohakhali is respectively, 2519 μg/m3, 376 μg/m3, 547 μg/m3 and 435 ppm; Farmgate- 7730 μg/m3, 752 μg/m3, 289.92  μg/m3, 590 ppm; Science lab- 5726 μg/m3, 113 μg/m3, 169.93 μg/m3, 500 ppm. Mogbazar- 5726 μg/m3, 339 μg/m3, 383.53 μg/m3, 475 ppm.  
The concentrations of sulphur dioxide, nitrous oxide and carbon dioxide in the air have been increasing over the years. In winter, smog becomes a part of the daily life of the city dwellers. 
Department of environment has mentioned the sources of air pollution in urban area – 60% pollutants from brick kilns; 18%  from road dust, soil dust;  10% from vehicles smog; 10% from burning of biomass; 10% from construction activities.                                                                                                             
As urban population and urban economic activities increase, more land is needed for housing, industries and commercial units. Construction of unplanned buildings, roads and earth excavation for land development lead to soil erosion. Increased demand for bricks is the outcome of an expanding construction industry, which follows rapid urbanization. To meet this demand, the number of brickfields keeps on increasing in the outskirts of urban areas. Growing numbers of brickfields mean further loss in prime agricultural land. Brickfields are also responsible for air pollution in the area. 
Noise has become a part of urban living creates annoyance, hampers mental and physical peace, and may induce severe damage to public health and environment. The source of most outdoor noise worldwide is transportation systems, including motor vehicle noise, aircraft noise and rail noise.  In Dhaka city, the average noise level of selected industries, hospitals and traffic places is respectively 87.09 dB, 70.58 dB, 100.79 dB which crosses the standard level of noise (Survey, 2015). The noise level of traffic place was higher than hospital and traffic places because vehicle horns make more noise intensity. Frequent exposure to noise at a level of between 80-100 decibels is likely to lead hearing loss. High level of noise can cause high blood pressure and other cardio-vascular disorders.                                                                                                                   
Disposal of solid wastes in all urban areas is inadequate. Household garbage, industrial wastes and infectious wastes from clinics and hospitals are all dumped in the same place. People also dump their garbage anywhere they find convenient, in front of others people’s homes, in drains meant for carrying wastewater, in rivers and on roadsides. 
High-rise apartment buildings may seem to be the answer to the housing problem of growing city where space is also limited. Unplanned proliferation of high-rise buildings sprouting in odd places throughout the urban landscape is a threat to its environment. Site selection and construction of high-rise buildings should be guided by zonal planning and should follow certain building codes. 
Increase in urban population has created a tremendous pressure on the existing network of intra-urban and inter-urban roads and highways as both the number and the volume of vehicular of traffic increases within the city or in its outskirts at specific time of the day, especially during rush hours. The number of motorized vehicles plying in streets of Dhaka was around 140,000 in 1995, 185,000 in 2000 and 290,000 in 2005. Now it is around 3, 85,000. Apart from that, there is a question of registration and non-registration. Motorized vehicles are escalating day by day. Two stroke three wheelers, diesel powered trucks and buses and defective motor vehicles of all types are responsible for the emission of NOx, SOx, CO, CO2 and hydrocarbons. 
In this perspective, it is urgent to ensure good participatory governance in managing environmental hazards and natural resources with the public participation from a cross-section of society. We have to reduce water, air, noise, radioactive and land pollution; unplanned construction of high-rise buildings all over the city and setting buildings codes; ensure proper solid waste disposal system; improvement of health care services and other social infrastructures; practical and functioning urban poverty alleviation programs; improvement in the public utilities services and their equitable distribution; improving the condition of urban squatter settlements. 
It is important of proper planning and maintenance of urban open spaces such as, parks and green belts around large cities where areas in the outskirts of the city are reserved for vegetation. Planning of the transport system, where an appropriate strategy of road pricing may be introduced for specific areas within the urban area to deal with traffic congestion. Ensure the better management of existing road networks and effective traffic management. We have to address green cities and countrywide image building, urban governance, resource efficiency and coordination among agencies, policy coalitions and change makers for disaster preparedness; conservation of common resources. 

The writer is an environment analyst


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Editor : M. Shamsur Rahman

Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.

Editor : M. Shamsur Rahman
Published by the Editor on behalf of Independent Publications Limited at Media Printers, 446/H, Tejgaon I/A, Dhaka-1215.
Editorial, News & Commercial Offices : Beximco Media Complex, 149-150 Tejgaon I/A, Dhaka-1208, Bangladesh. GPO Box No. 934, Dhaka-1000.

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