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ASSESSMENT AND DYNAMICS OF URBAN GROWTH

IN THE CITY OF KOLKATA, INDIA

Chandana Mitra, J. Marshall Shepherd and Thomas R. Jordan

The world has seen, and is still seeing the rapid development and spread of urban areas.

Cities and towns have sprouted up everywhere around the globe. Villages are transforming into

towns and towns into cities, attracting more and more people, and adding to urban expansion.

Population increase and industrialization are the key factors behind such a phenomenal change in

spatial structure.

India, the second most populated country in the world, has experienced large-scale

development in and around its urban areas. The city of Kolkata in eastern India, the focus herein,

has being aggressively multiplying in size over the last three decades. However, the real

population explosion took place between 1940 and 1950, during the Indian independence phase,

although growth as such is still continuing (Chakraborty, 1990).

Closely associated with the morphology of any city are its past and present populations

that have adhered to certain social and economic customs and followed distinctive occupations

(Dutt et al, 1989, 151). Kolkata was the first major city developed by the British East India

Company in the early 1700s. The East India Company built their first fortified construction, Fort

William, to protect them from the other colonial aspirants. It was around this fortified structure

that the city of Kolkata grew and nurtured itself. It was a garrison town first, then the Company’s

town, next a provincial city, and later the headquarters of the British India government (National

Atlas and Thematic Mapping Organisation (NATMO) 1996.). This established a level of

importance for the city and stimulated significant growth in size over the years. The Kolkata

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megalopolis began with a population of 100,000 in 1735 and grew to 15 million (KMDA Report

2005), reflecting largely uncontrolled growth over the past 300 years.

This Chapter assesses the extent of urban sprawl of Kolkata over the years and

characterizes its growth pattern using historical maps and satellite images. To the best of our

knowledge, this study represents possibly the most thorough spatial as well as temporal

evaluation of Kolkata’s urban dynamics, spanning several centuries. Also presented is a detailed

assessment of the political and natural dynamics and influences governing urban growth in

Kolkata. Specific methods used are historical cartographic analysis and more recent

technological advancements in remote sensing and modeling. Particular attention is also paid to

future studies as to how environmental factors such as urban heat island and pollution will affect

climatic patterns as Kolkata transforms from Dominique Lapierre’s ‘City of Joy’ into a ‘City of

Concrete’. This study also paves the way for further research in other similar cities, especially

coastal cities that have similar terrain. The local government can also benefit from this study as

policies and decentralization techniques can be molded depending on the study.

STUDY AREA

Kolkata is located in the eastern part of India at 22°82′N 88°20′E. A 300 year old city, it

has witnessed great development over the centuries, spreading linearly along the banks of the

river Hooghly (Fig. 29-1). Kolkata still retains many of its former attributes as the first major city

of India – the magnitude of its population, its volume of trade and commerce, the avenues of

employment that it offers, the variety of its inhabitants speaking diverse languages that give it a

cosmopolitan character, and its continued importance as a center of art and culture (Roy, 1996).

The Kolkata Municipal Corporation administers an area of 185 km² or 71.43 sq. miles

(Metropolis 2005). The city is at sea level, the average elevation being 1.5 to 9 meters

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(approximately 5 to 30 feet), although there are some natural depressions in the area, likely

remnants of dead river channels. The whole area falls in the Ganges Delta (Survey of India,

Topographical maps, No. 79 B/6, B/7).

However, the city has continuously expanded, and today the urban agglomeration

(Kolkata Metropolitan District or KMD) comprises 157 postal areas and is formally administered

by several local governments, including 38 local municipalities, 72 cities and 527 towns and

villages (Kolkata Postal Codes, 2007). The suburban areas of (KM D) incorporate parts of the

districts of North 24 Parganas, South 24 Parganas, Howrah, Hooghly and Nadia (Metropolis

2005).

Fig. 29-1: Calcutta Metropolitan Area, Dutt

and Geib (1987 p.133)

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LITERATURE REVIEW

The world is gradually becoming highly urbanized, with population living in the cities

increasing from five per cent of the global population in 1900 to nearly 50 per cent in 2005

(Maktav et al., 2005). As climate change becomes a more pronounced phenomenon causing

concern, it is necessary to understand how changes in the urban environment affects the physical,

social and climatic pattern in and around the city. Increased urbanization brings with it attendant

development involving the use of materials and construction of infrastructure and structures that

act as heat absorbers. A heated urban environment will influence phenomena such as the water

cycle and pollution level, which may bring changes in the climatic pattern and thus influence

physical and social patterns of the city (Shepherd 2005).

However, first the extent of urbanization must be assessed, using either traditional

methods like paper maps and surveying, or new methods like GIS and remote sensing. A large

body of research has been done in the field of assessing the urban extent, especially in the

developed countries of the west. Not much research has been done in developing countries where

the impact of urbanization on local and regional levels may be more profound. In developing

countries, overpopulation and unplanned development have given urbanization a more damaging

aspect.

As mentioned above, it is necessary to analyze the extent of urbanization and measure its

impact on the people and environment. Traditional methods for gathering demographic data,

censuses, and maps using samples are impractical and unsatisfactory for most urban management

purposes. Remote sensing – as a technique for observing the surface of the Earth from different

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platforms – and Geographic Information Systems (GIS) can help to solve the problems of

traditional methods by providing up-to-date spatial information.

This trend of using GIS and remote sensing for understanding growth patterns of cities in

developing countries began in the 1970s (Maktav et al., 2005). Since 1972, numerous technical

improvements have led to the second generation of Earth observation satellites, such as Landsat1,

SPOT2 and IRS

3. From 1999 onward, one can distinguish a third generation of Earth observation

satellites with very high geometric resolution (IKONOS-2, Quickbird-2, etc) (Maktav et al.,

2005). The convergence of GIS, remote sensing and database management systems has helped in

quantifying, monitoring, modeling and subsequently predicting this dynamic phenomenon of

urban sprawl (Sudhira et al., 2004).

Small (2002) performed a comparative Spectral Mixture Analysis (SMA) of Landsat 7

Enhanced Thematic Mapper (ETM+) imagery for a collection of 28 urban areas worldwide to

provide a physical basis for a spectral characterization of urban reflectance properties.

In 2002, Paul C Sutton of the University of Denver used nighttime satellite imagery to

delineate urban areas. Maktav, Erbek and Jurgens (2005) attempted to highlight the importance

of remote sensing as one of the most reliable mechanisms to assess the consequences of

urbanization quickly and effectively in developed and developing countries. Different sensors on

different platforms (HRSC-A5, aerial cameras, LIDAR

6, satellite sensors) acquire high-resolution

3-D surface information that is needed to model the air movement within a city (Maktav et al.,

2005).

It is evident that monitoring of urban land use change using techniques of remote sensing

and GIS and its subsequent modeling is lacking in the context of India (Sudhira et al., 2004),

although some few instances of such work do exist. Sudhira, Ramachandra and Jagadish (2003)

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used remote sensing and GIS to understand the pattern and sprawl of the city of Udipi in the

Mangalore region of India. They used standard image processing techniques such as image

extraction, rectification, restoration and classification in the study. They found that the rate of

development of land in Udipi was outstripping the rate of population growth, which implied that

the land was being consumed at excessive rates. Between 1972 and 1999, population in the

region grew by about 54 percent (Census of India, 1971, 1981, 1991), while the amount of

developed land grew by about 146 percent (Sudhira et al., 2004).

Venugopal and Turcotte (1993) used IRS-1AISS1 satellite data transformed through

principal component analysis. The spatial resolution of the data-set was 72.5 meters. Thirty-six

classes derived from Isodata clustering were grouped to form five generalized land use/cover

categories for the Calcutta Metropolitan District. They mapped high, medium and low density

built-up areas for the District.

Some of the other cities of India that have been the focus of studies employing GIS

techniques and remote sensing include Ahmedabad, Surat and Vadodara (Jothimani, 1997),

Vadodara (Bhatt et al., 2006), Dhanbad (Srivastava, 2000), Hyderabad (Lata et al., 2001),

Bhopal (Saxena, 2003), and Allahabad (Srivastava and Gupta, 2003). This review highlights the

value of using cartographic and geographic information sciences in studying urban growth and

sprawl, eventually aiding in policy framing exercises. It also highlights the need for an objective

and quantitative study of Kolkata, a fast-developing city with historical evidence of incessant

unplanned growth of populace due to various political and social issues. This study can be an

ideal case study for future studies with similar conditions.

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RESEARCH OBJECTIVES

The overarching objective of this chapter is to quantify the extent of urban sprawl in the

city of Kolkata and to reveal how the city has developed in the past 300 years, despite natural

and human induced barriers. The first objective is to delineate the growth of the city and the

extent of urban sprawl through an analysis of historical maps and satellite images. The second

objective is to place Kolkata’s urban growth within the context of different factors that have

contributed to this population explosion and molded its growth: the natural and political factors

that have profoundly influenced the sprawl in the twentieth century will be highlighted. The third

objective pays particular attention to future studies as to the effects of uncontrolled urban

growth, present and future, on the local and regional climatic patterns of Kolkata. The chapter

also features some examples showing how land use/land cover (LULC) changes have occurred

over the decades due to population pressure.

DATA SETS

The maps and images used to delineate the urban growth of Kolkata city are historical

paper maps, Landsat images (1990 and 2000), and topographical maps. Of the Landsat images,

the first is a Landsat TM image dated 11/14/1990. It is a World Reference System 2 (WRS 2)

image and the path & row is 138 & 044 respectively. The second image is a Landsat ETM

satellite image dated 11/17/2000. It is also a WRS 2 image and the path & row is 138 & 044

respectively.

In addition to these two images, a historical paper map (scale 1:100,000) of Kolkata city

showing the growth of the city from before 1756 to 1990 was used (National Atlas & Thematic

Map Organization 1996). Two topographical maps (scale 1:50,000), #s 79 B/6 & 79 B/7,

showing Kolkata city and adjoining area are also used (Survey of India).

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METHODOLOGY

In this study, traditional cartographic sources like paper maps were employed because

there were no existing digitized historical maps of Kolkata available. The results from

digitization were validated by remotely sensed images from recent years. The topographical

maps and the city growth map were both paper maps, so the first step was to scan the maps and

have them digitally available. The scanned topographical maps were then rectified with the base

paper maps using latitude/longitude coordinates found along the margins of the maps. The two

topographical maps were mosaiced together to have a larger view of the area.

Fig. 29-2A: Digitized Map of Kolkata Showing Urban Growth:

Before 1756-1793.

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Fig. 29-2 B: Digitized Map of Kolkata Showing Urban Growth:

1793-1947

Fig. 29-2 C: Digitized Map of Kolkata Showing Urban Growth:

1947-2000.

The Kolkata urban sprawl map did not have any coordinates, so it had to be

georeferenced to the topographical map. For this process, 16 ground control points were chosen

on both maps to georeference one to the other using Leica Geosystems Imagine 9.1 software. To

facilitate further analysis, all datasets had to be precisely registered and transformed into the

same coordinate system. The historical growth map was based on geographic coordinates and

was transformed to Universal Transverse Mercator (UTM) grid-system coordinates. The growth

map and the Landsat images could not be overlaid to compare urban growth without the same

coordinates, therefore the images were also transformed from geographic coordinates to UTM

coordinates using the ArcGIS 9.1 software. After all the transformations were complete, the

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study area lay in the UTM system, Zone 45 N and cast on the World Geodetic System (WGS)-84

datum.

All the maps used in the analysis were published as paper products, so none of the

features of interest had been previously digitized. The extent of growth in the city was delineated

using heads-up digitizing methods from the urban growth map and Landsat images using the

ArcGIS software. Although the process of digitization was very time consuming and difficult, it

was necessary to reveal the phases of growth in different time frames, beginning from before

1756 to 1990. The result was a unique view of the growth history of Kolkata over this time

period.

The next step was to overlay the digitized maps onto the satellite images to further

digitize and detect the changes in the growth pattern between 1990 and 2000. The overlaying of

the digitized growth map over the 2000 satellite image showed an extension in area from the

1990 urban sprawl. An unsupervised classification on the image was done on the 2000 image,

but the results were not completely satisfactory. Since the unsupervised classification did not

give the desired result, a portion of the digitization was done based on visual interpretation. The

areal extent of the city in different phases was calculated post-digitization, using the attribute

table of ArcGIS 9.1 software.

RESULTS AND DISCUSSION: GROWTH FACTORS AND PATTERNS

A major factor contributing to the influx of millions of refugees across the border was

India’s independence from British colonial rule in 1947. Many of them from East Pakistan

settled in Calcutta Metropolitan area on whichever plots of land were available, without regard to

planning or other regulations. Another factor contributing to urban sprawl was the influx of

people from the surrounding non-urban and less developed areas to the city (Roy, 2003). Kolkata

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is the most important city as compared to other cities in the eastern part of India. It has become

the target city for east India and a source for financial advancement for many people. Population

growth and the drive for economic development have led to unplanned and sporadic expansion

of the mega city. Kolkata, from its days of inception, was never a planned city. It grew

haphazardly around the port, the old fort and the ancient Barabazar market by the river (Dutta,

2003). However, little research has been done to measure the extent of damage done by the

unprecedented urban sprawl.

The digitization of the urban growth boundaries over a temporal span of approximately

300 years has highlighted the fact that the city of Kolkata has spread out in all directions, though

growth is maximum to the east of the river Hooghly. The growth was gradual up to 1947, just

after which there was a population explosion, with refugees coming in from Bangladesh due to

the India-Pakistan partition at the time of independence of the two countries. The influx of

migrants had started before independence, as people were somewhat aware of the possible

aftermath of the post-independence partition of the country. This fact is supported by the census

data for the 1931– 1941 decade when the population of Kolkata city increased by 77 percent

(NATMO 1996). The rate of increase of population became faster after India’s independence in

1947.

People from Bangladesh and neighboring states continue to settle in Kolkata city even

today. The economic push factors that motivate people to leave Bangladesh are political

instability and economic depression, poverty, lack of employment opportunities, struggle for

livelihood, forced grabbing of landed property from minority groups, social insecurity, and lack

of industrialization (Datta, 2004).

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The city grew more or less naturally and gradually till 1947, though the influx of refugees

had already started from the 1930s. After 1947 the city suddenly burst out in all directions,

reflecting the sudden increase in the population and thus, in the city limits.

Table 29-1 shows the growth in area from the beginning of the 1700s to the year 2000.

The striking feature to be seen in the calculations is the change in area after 1947. This agrees

with the previous findings with regards to the influx of refugees in huge numbers just before and

after Indian independence in 1947. There was a three-fold increase in the area of the city during

this time span around Indian independence. The yearly spatial growth was also high (23.30 sq.

km. or approximately 9.0 sq. miles) up to 1990. Further, it can be seen that the yearly growth of

the city limits did not slow down even in the next decade (1990 - 2000)—it was a high 29.47 sq.

km. (11.38 sq. miles) each year. This demonstrates that the city continued to grow fairly rapidly,

in fact, at an even higher rate than before. Figure 29-2 A, B and C is a graphical representation of

Table 29-. 1.

Year Total Area (sq. km) Change in Area (sq.

km)

Area Change/year

(sq.km)

Before 1756 3.46

1756-1793 33.57 30.11 0.8137

1793-1856 135.88 102.31 1.6239

1856-1947 361.27 225.39 2.4768

1947-1990 1363.36 1002.09 23.3044

1990-2000 1658.12 294.76 29.476

Table 29-1: Change in area of Kolkata over years in sq. km.

During the last two decades, the population of the city of Kolkata has only been growing

at the somnolent rate of 2 per cent per decade. In contrast, the Kolkata Metropolitan District

(KMD), which includes the rural tracts and townships that ring the city, has been expanding

spatially at a decadal rate of over 18 percent (Census of India, 1991; Roy, 2003). This

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information is alarming enough for the government and planners to think and rethink the

magnitude of damage such a high rate of expansion could have on the overall environment of the

city.

The authorities have overlooked the possible environmental degradation that might set in

due to the gradual filling up of the city wetlands in the east. Some of the fastest growth is

occurring on the eastern fringes of the KMD. This involves state-controlled developments, such

as Salt Lake City and the proposed New Calcutta at Rajarhat, as well as a flurry of private

building activities, especially in the sphere of middle class housing (Roy, 2003). The Salt Lake

City (India), a satellite town east of Kolkata, developed by the government in 1960s, which was

a 15 sq. km. (5.8 sq. mile) stretch of wetland and is now being transformed into a concrete

jungle. It took approximately seven years to fill this wet zone with sand. Five-mile long pipes

were laid down to transport the sand and silt from Ghushuri to Salt Lake. It now supports a

population of 167,848 (Census of India, 2001). Additionally, unplanned development in the

southeastern part of Kolkata is expanding, gradually drying the wetland areas.

FUTURE RESEARCH

The buildings, concrete, asphalt and the human and industrial activity in urban areas

cause cities to maintain higher temperatures than their surrounding countryside. This

phenomenon of increased heat is known as an urban heat island. It is known that the air in an

urban heat island can be as much as two to ten degrees higher than rural areas surrounding the

city (Shepherd 2005). The roughness of the urban buildings and urban pollution also contribute

to the increase of heat in the cities. The urban heat island effect in turn affects the microclimate

of the city and the intensity of rainfall decreases or increases in and around the cities (Shepherd,

2005).

Salt Lake City, Kolkata - Satellite Town

Salt Lake City, Kolkata - Satellite Town

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It is apparent that as unplanned and unrestrained development occurs in the cities, the

environmental health of the cities will deteriorate. But, unless appropriate steps are taken, there

will be no other option left but to continue living in those deleterious conditions. The prospect of

continued growth in Kolkata raises a number of serious questions about urban growth and

Kolkata in particular. For example, what happens when built up areas increase in a city? What

will happen to Kolkata in the future? Will urban growth affect the environment? Will the

uncontrolled growth and land use change of Kolkata have any impact on the precipitation in and

around the city?

The above questions open up new avenues of research that could help improve the

harmful condition into which the city of Kolkata is gradually being forced. Our ongoing research

will encompass the projection of the future growth of Kolkata in the next 25 years, using the

SLEUTH model, a cellular automata model7. SLEUTH models urban growth through the

analysis of rasterized maps representing parameters such as land use, existing and future

transportation corridors, urban area, excluded areas and slope. This helps to foresee the areas

where the pressure of growth will be greater. Planning of the city can be done on the lines of this

projection, so that there is uniformity in development.

The results from the SLEUTH model will then be fed into the Weather Research and

Forecasting (WRF) model to see if climate variables such as precipitation will increase or

decrease around the city due to this undaunted urban growth. The study will involve an analysis

of hundred years of rainfall data from weather stations in and around Kolkata. The results from

this study will examine how urban growth affects climate, and will contribute to original

research in this area.

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NOTES

1. Landsat – Derived from Land Satellite.

2. SPOT - Satellite Pour l'Observation de la Terre

3. IRS – Indian Remote Sensing Satellite

4. DMSP OLS – Defense Meteorological Satallite Program (DMSP) Operational Linescan

System (OLS)

5. HRSC-A – High Resolution Stereo Camera Airborne

6. LIDAR – Light Detection and Ranging

7. Cellular automata model

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