1. INTRODUCTION:

The city is changing day by day in terms of population, size, settlement (types, density etc.). Because of the rapid influx of population from the surrounding area and also from the Bangladesh especially in Kolkata city are the major causes of population growth and loss of urban heritage in Kolkata city. Most of the people migrate to spend better quality of life and various opportunities. “Many historic cities do not contain individual buildings of exemplarymerit, but as a precinct they represent a way of life and living which is an intangible characteristic of urban heritage” (UNESCO, 2010). According to the United Nation’s population projection in 2014, 54 percent of the people live in urban areas and it is estimated that in the year 2015 66 percent of the people will be resided in urban areas where 90 percent of the growth will be concentrated in Asia and Africa (United Nations, 2015).

In case of developing countries like India, the number of population is increasing day by day where according to the latest census 31 percent of the people lives in urban areas and 68 percent of the people lives in rural areas. In case of the most of the metro cities of India most of the residents faced lack of basic amenities, drinking water supply etc.

Historical sites face many challenges, like accelerating globalization, structural, social and demographic changes as well as environmental problems and urban growth. As urban growth is a double faced process it is the concentration of population in urban areas due to supplied services that are missing in rural areas, at the same time it is a decline of socio-economic areas agglomerations. This increase in population happens due to the concentration of economic activity, which is an important determinant, and the result of urbanization. This results in introducing unbalanced trends which destroys human cohesion and builds social exclusion in cities and regions. Through urbanization, people ignore their identities and traditions seeking adequate services and a better lifestyle leading to the disappearance of existing urban fabric that creates an undefined urban pattern. The right balance between restoring and preserving unique cultural heritage has to be set to enable future proof urban development. Urban growth affects the efficiency of production and economic growth, and the way agents interact and live in cities. Understanding its implications and causes has captured the interest of economists, architects and urban planners in the past and deserves to continue doing so in the future.

Cultural heritage is an essential resource for sustainable human development, economic development with employment opportunities and their protection is not only a moral call, but also a necessary financial investment to progress towards the creation of inclusive and sustainable cities (Girard, 2013; Angrisano et al. 2016; Axelsson et al. 2013). The rate of urbanization in India is very high which causes an extensive pressure on natural resources which possessesa threat to cultural heritage also. Because of the continuous increase in urban population Kolkata city population is increasing day by day. As a result because of the lack of open places for housing at lower prices most of the people have to stay in the slum. Kolkata is a city which experiences recently lack of open spaces which accelerates the loss of urban heritage in Kolkata city. Cities and towns act as catalyst for cultural, social and economic development (United Nations, 1987; Musacchio, 2013; Reed et al. 2016; Wu, 2013). Half of the world’s population already lived in urban settlement. Historical sites represent the heart of the cities which play a very important role in creating a stimulating and economically attractive environment for inhabitants.

In this article an attempt has been made to find out the loss of urban greeneries of 1990 and 2015 and the loss of urban heritage in Kolkata city. Side by side effort has been made to find out the major causes behind the loss of heritage buildings.H

2. Study Area:

Fig 1 Areas of study

Source: Kolkata Metropolitan Development Authority and Kolkata Municipal Corporation

KMA (Fig 1) is one of the largest agglomerations in the country and also one of the oldest. The concept of Kolkata Metropolitan Area (formerly CMD i.e. Calcutta Metropolitan District) was introduced by the Calcutta Metropolitan Planning Organization (CMPO) by the Use and Development of Land Control Act of 1965. According to this Schedule Act the area of the then Calcutta Metropolitan District was the 1380 Sq. Km.Now at present it extends over an area of 1841.47sq.km.(Table 1) in the deltas of River Hooghly, covering the whole of Kolkata district and parts of five other districts, namely, 24-Parganas (South), 24-Parganas (North), Howrah, Hooghly and Nadia. The boundary of this area was delineated by the Kolkata Metropolitan Development Authority (KMDA) and all types of planning of this area is under the control of KMDA.

It is mainly a developmental agency with the purpose of carrying out major infrastructure development within KMA (Kolkata Metropolitan Area). After the journey of nearly 51 years, KMDA has still the authority for urban planning and development within KMA. One of the important characteristics of this renowned Metropolitan area is that it is bounded by the rural adjacent areas.

Table: 1 Present Composition of KMA

Units	No’s	Area (Sq.km)
Municipal Corporations	3	282.23
Municipalities	39	661.37
Census Towns	155	364.53
Out Growth’s	6	4.68
Rural Areas	394	518.77
Total KMA		1831.58

Source: Census of India, 2011 & KMDA.

3. DATABASE AND METHODOLOGY:

The data set for this study is comprised of five Landsat images recorded from 1990 and 2015. Detailed description of those images discussed below (Table 2)

Table 2 Detailed information of utilized satellite imagery

Acquisition Date	Sensor	Spatial Resolution	Projection
08-03-2015	OLI-TIRS	30m	WGS 84 UTM 45 N
14-11-1990	TM	30m	WGS 84 UTM 45 N

Source: US Geological Survey, 2015.

Two sets of landsat satellite images were used here. Landsat Thematic Mapper (TM) and landsat OLI 8 images (with path/row 138/45). At the time of layer stacking of those images thermal band was excluded. Digital maps published from the KMDA, has been digitized and geo-referenced from hardcopy topographic maps with scale of 1:50,000. This map has been used as a reference image. It is mainly used for geometric correction of those satellite images and to collect some ground truth information. Finally, ground information was collected between the years 1980 until 2015 to get land use/land cover information. Then supervised classification algorithm was used to scrutinize the land cover types.

3.1. Image Processing:

The images were geometrically corrected and geocoded to the Universal Transverse Mercator (UTM) coordinate system by using a reference image which has been geo-referenced previously by the topographical sheets which were provided by the Survey of India (SOI). This minimum of 30 randomly distributed ground control points (GCPs) were selected from the topographical sheets for georeferencing the image. Resampling technique was performed using a nearest neighbour algorithm technique. Image transformation technique was used with root mean square (RMS) error of 0.1 pixels indicating that the image was accurate to within one pixel.

3.2. Normalized Difference Vegetation Index (NDVI)

NDVI techniques have been applied to find out the percentage of greeneries around Kolkata city. NDVI=NIR-RED/NIR+RED

It helps to find out or to analyze the vegetation areas of an area. In this urban area to scrutinize the urban vegetative area NDVI indices have been used which clearly differentiate the urban areas with vegetation area, otherwise it has been considered as errors.

4. DISCUSSION AND ANALYSIS:

Kolkata city was capital of India till 1916 then Kolkata city which was under the British rulers. Its origin dates back to 1690 when a factory was set by the Job Charnock for the East India Company and he is the Founder of Calcutta City. Between the year 1773-1911, Calcutta was the major trade centre of East India Company and also the Capital of India. After the Independence huge number of refugees from Bangladesh, formerly ‘East Pakistan’ came to Kolkata which is the major cause of huge population increase in Kolkata city. Kolkata city is situated on the east bank of the river Hooghly (Hugli) on the lower Gangetic delta which is part of the Bengal basin. It stands on a thick alluvial deposit of the great antiquity. Geologists agree that Kolkata is a part of submerged sundry trees found beneath the city (Nair 1986)

The cancerous growth of Calcutta as a primate city which is rounded by a backward agricultural hinterland and it is supported by any hierarchical structure of urban centre has become a subject matter of study of politicians; planners and social scientists in India and drawn the attention of urban researchers throughout the world (Munsi, 1975).

Figure 2. Population Growth in Kolkata Metropolitan Area

The flow of migration from the other states of India and from the other regions of West Bengal to Kolkata now-a-days is increasing due to the concentrated development in business outsourcing, information technology, information technology enabled services, medical transcription, etc in the city core areas. Other than that the commuters from different districts near and around Kolkata city used to come to city for their daily work.

Figure 3. Lack of Vacant Space and Loss of Urban Greeneries in and around Kolkata city between 1980 and 2015

By analyzing NDVI techniques of the year 1990 and 2015 it has been found that, the vegetation

area is decreasing day by day. By the NDVI classification it has been found that after the twenty five years i.e. 1990 and 2015 most of the vegetation in the city core areas has been decreased because of the huge urban growth. Due to urban growth in the city core areas and peripheral areas of Kolkata city most of the urban greeneries have been decreased. The loss of green space is accelerated by the low prices of land as the prices of reclaimed land from green space areas are very low. Due to crisis of vacant space people are unable to settle in the city core areas as most of the buildings in city core areas are old buildings and most of the buildings are single storied. For this reason real estate developers renovate those houses and converted it into the multi-storied house which helped the people to stay under one roof. This is the main reason behind the reduction of heritage buildings in Kolkata.

Measures taken by Kolkata Municipal Corporation for heritage conservation:

· Responsibilities of the owners to maintain and preserve the heritage buildings.

· KMC can identify the buildings as heritage buildings and differentiate them into multiple categories.

· Ownership of heritage buildings and rules of heritage buildings.

· Power of taxes on heritage buildings.

Reasons behind the loss of urban heritage:

From the field survey it has been found that most of the heritage buildings are located in the central location of the city, as most of the areas are flourished from the British period. Most of the people in this area had been built up their house in the good location in the city areas. On that all heritage houses the pressure of population on land are very low. If the real estate developers can convert it into a multi storied buildings then it can accommodate large number of people under one roof. This is the main reason behind the reduction of urban heritage buildings.

5. CONCLUSION:

Cities are living environments that must change and adopt new plan, programs and policies for its inhabitants. Urban conservation needs improved management to minimize the negative impacts on urban heritage for the future planning and development of the region.

Urban Conservation needs requires improved management of change to mitigate the potential negative impacts on the heritage significance of the historic urban environment. To do this the heritage values of the city need to be clearly identified and mechanisms for their protection and management established and integrated into the overall planning framework. These mechanisms must take account of pressures for modernization, improved living standards, and new environmental requirements. Social change can have a major impact on the historic urban fabric. A better understanding of the physical impact of social change is key to identifying new mechanisms for managing such impacts and finding ways to successfully accommodate advances in civil society that retain the heritage significance of an urban area. Clearly identifying intangible heritage values that contribute to the heritage significance of an urban area is also vital. The methods used in this study will be helpful to the other areas also. It is also needed for the future planning and development of the region. This type of study will focus a new light over the new researchers in this field. The reasons behind the loss of cultural heritage that has been described in this paper will help the policy makers to take various planning strategies to reduce the cultural heritage of the city.

6. REFERENCES:

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Received on 07.05.2019 Modified on 10.06.2019

Res. J. Humanities and Social Sciences. 2019; 10(4):969-972.

DOI: 10.5958/2321-5828.2019.00158.X