Cities origin can be traced back to the river valley civilizations of Mesopotamia, Egypt, Indus Valley and China. Initially these settlements were largely dependent upon agriculture; however, with the growth of population the city size increased and the economic activity transformed to trading1. The process of urbanisation gained impetus with industrial revolution 200 years ago and accelerated in 1990’s with globalization and consequent relaxations in market economy.
Urbanisation refers to the growth of the towns and cities due to large proportion of the population living in urban areas and its suburbs at the expense of rural areas2. In most of the countries the total population living in the urban regions has extensively accelerated since the Second World War. Rapid urbanisation during the 20th century is evident from the dramatic increase in global urban population from 13% (220 million, in 1900), to 29% (732 million, in 1950), to 49% (3.2 billion, in 2005) and is expected to increase to 60% (4.9 billion) by 2030 and 9.6 billion in 20502. Current global population is 7.4 billion and urban population has been increasing three times faster than the rural population, mainly due to migration in most parts of the world. People migrate to urban areas with the hope of a better living, considering relatively better infrastructural facilities (education, recreation, health centres, banking, transport and communication), and higher per capita income. Unplanned urbanisation leads to the large scale land use changes affecting the sustenance of local natural resources. Rapid unplanned urbanisation in most cities in India has led to serious problems in urban areas due to higher pollution3 (air, water, land, noise), inequitable distribution of natural resources, traffic congestion, spread of slums, unemployment, increased reliance on fossil fuels, and uncontrolled outgrowth or sprawl in the periphery. Urbanisation is one of the demographic issues being investigated in the 21st century, understanding spatial patterns of changes in the land and visualization in advance of growth is imperative for sustainable management of natural resources and to mitigate changes in climate3. This would help the city planners in planning to mitigate the problems associated with the increased urban area and population, and ultimately build sustainable cities.
Bangalore is experiencing unprecedented rapid urbanisation and sprawl in recent times due to unrealistic concentrated developmental activities with impetus on industrialisation for the economic development of the region2. This has led to large scale land cover changes with serious environmental degradation, posing serious challenges to the decision makers in the city planning and management process involving a plethora of serious challenges such as climate change, enhanced emissions of greenhouse gases (GHG)3, lack of appropriate infrastructure, traffic congestion, and lack of basic amenities (electricity, water, and sanitation) in many localities, etc. Apart from these, major implications of urbanisation are:
- Urbanisation and loss of natural resources (wetlands and green spaces): Urbanisation during 1973 to 2016 (1005% concretization or increase of paved surface) has telling influence on the natural resources such as decline in green spaces (88% decline in vegetation), wetlands (79% decline), higher air pollutants and sharp decline in groundwater table. Figure 1 depicts the unrealistic urban growth during the last two decades. Quantification of number of trees in the region using remote sensing data with field census reveals that there are only 1.5 million trees to support Bangalore's population of 9.5 million, indicating one tree for every seven persons in the city4. This is insufficient even to sequester respiratory carbon (ranges from 540-900 g per person per day). Geo-visualisation of likely land uses in 2020 through multi-criteria decision making techniques (Fuzzy-AHP: Analytical Hierarchal Process) reveals calamitous picture of 93% of Bangalore landscape filled with paved surfaces (urban cover) and drastic reduction in open spaces and green cover. This would make the region GHG rich, water scarce, non-resilient and unlivable, depriving the city dwellers of clean air, water and environment.
|gure 1: Urban growth in Bangalore (based on temporal data acquired through space borne sensors)
Field investigations (during 2015-16) of 105 lakes reveals that 98% lakes have been encroached for illegal buildings (high raise apartment, commercial building, slums, etc.) and 90% of lakes are sewage fed. Also, lake catchments are being used as dumping yards for either municipal solid waste or building debris. Indiscriminate disposal of solid and liquid waste (rich in organic nutrient) has enriched nitrate levels in the surrounding groundwater resources, threatening the residents’ health (such as kidney failure, cancer, etc.). Washing, household activities, vegetable cultivation and even fishing was observed in few contaminated lakes. Unauthorised construction in valley zones, lakebeds and storm water drains highlight the apathy of decision makers while mirroring weak and fragmented governance. This is correlated with the increase in unauthorized constructions violating town planning norms (city development plan) which has affected severely open spaces and in particular water bodies.
Large-scale fish mortality in recent months further highlights the level of contamination and irresponsible management of water bodies. Sustained inflow of untreated sewage has increased the organic content beyond the threshold of remediation capability of respective water bodies. Increasing temperature (of 34 to 35 °C) with the onset of summer, enhanced the biological activities (evident from higher Ammonia and BOD -Biochemical Oxygen Demand) that lowered dissolved oxygen levels leading to fish death due to asphyxiation.
- Floods: Conversion of wetlands to residential and commercial layouts has compounded the problem by removing the interconnectivities in an undulating terrain. Encroachment of natural drains, alteration of topography involving the construction of high-raise buildings, removal of vegetation cover, reclamation of wetlands are the prime reasons for frequent flooding even during normal rainfall post 2000.
- Decline in groundwater table: Water table has declined to 300 m from 28 m and 400 to 500 m in intensely urbanised area such as Whitefield, etc. over a period of 20 years.
- Heat island: Surface and atmospheric temperatures have increased by anthropogenic heat discharge due to energy consumption, increased land surface coverage by artificial materials having high heat capacities and conductivities, and the associated decreases in vegetation and water pervious surfaces, which reduce surface temperature through evapotranspiration. An increase of ~2 to 2.5 ºC during the past three decades highlights implication of explosive urban growth on local climate, necessitating appropriate strategies for the sustainable management of natural resources.
- Increased carbon footprint: Drastic increase in electricity consumption was observed in certain corporation wards due to the adoption of inappropriate building architecture in tropical climate. Per capita electricity consumption in the zones dominated by high raise building with glass facades ranges from 14000-17000 units (kWh) per year compared to the zones with eco-friendly buildings (1300-1500 units/person/year)3.
Emissions from transport sector is about 43.83% (in Greater Bangalore) on account of large scale usage of private vehicles, and mobility related to job accounts for 60 % of total emissions due to lack of appropriate public transport system and haphazard growth with unplanned urbanisation. Higher fuel consumption, enhanced pollution levels due to the increase of private vehicles, traffic bottlenecks have significantly contributed to carbon emissions. Majority commute longer distances due to lack of integrated land use and mobility planning, thus contributing to emissions. Apart from these, mismanagement of solid and liquid wastes has aggravated the situation. Dumping of solid and liquid waste in water bodies has increased the anaerobic condition leading to emissions of greenhouse gases (methane, CO2, etc.).
Unplanned cities thus not only contribute to global climate change by emitting the majority of anthropogenic greenhouse gases but also are particularly vulnerable to the effects of climate change and extreme weather. This emphaises the need to improve urban sustainability through innovations while addressing technical, ecological, economic, behavioral, and political challenges to create cities that are low-carbon, resilient, and livable.
The smart cities mission launched by the Government of India recently (in June 2015) envisages developing physical, institutional, social infrastructure in select cities with central assistance targeted at improving the quality of life as well as economic visibility of the respective urban centres5. Four strategic components are (i) green field development through smart townships by adopting holistic land management, (ii) pan-city development through adoption of smart applications like transport, reuse and recycle of wastewater, smart metering, recovering energy from solid waste, etc., (iii) retrofitting to make existing area more efficient and livable by reducing greenhouse gas (GHG) footprint, improving power and treated water supply3, improving communication and infrastructure connectivity and security, (iv) re-development of existing built-up area, creation of new layout through mixed land use, adoption of appropriate floor area index (FAI) considering the level of existing and scope for improvement of infrastructure and basic amenities, which helps in keeping the city’s growth within the region’s carrying capacity4 and urban infrastructure becomes inclusive. This entails efficient decision making through (i) integrated land use planning as per the city’s requirements considering mobility, etc., to minimize mobility related to jobs; (ii) enhancement of the functional capacity through user friendly and economic public transport support; (iii) development of mass rapid-transport systems for easy mobility in inter and intra cities; and (iv) effective use of ICT’s as enabling technologies to improve the level of services. These measures have to be implemented quickly as most cities are in a civic and financial disarray because of senseless unplanned rapid urbanisation.
Environmentally sound urban centres with essential basic amenities and advanced infrastructures (such as sensors, electronic devices and networks) would stimulate sustainable economic growth and improvements in citizen services. The deployment of information and communication technology infrastructures for effective governance support social and urban growth through improved economy and active participation of citizens. Indian cities while exhibiting technological innovations and connectedness, should also focus on increased living comfort through adequate infrastructure, green spaces and essential basic amenities to every citizen.