2025 Volume 13 Issue 1 Pages 172-189
India surpasses all other nations in terms of population and about 330 million people reside on or within the 150 KM of the country's coastline which stretches across 9 states and 4 union territories (UTs) cover 7516.6 KM. People who are living in an extremely low elevation seacoast places are no longer safe because of regular rise in sea level due to global warming and other natural and artificial disasters/imbalances. Therefore it is quite difficult to manage and administer the population which are residing in the low-lying areas that are close to the ocean. Therefore an attempt is made in this paper to explore and analyze the low-lying areas and the cities/villages located along Indian coastal states/union territories that are very dangerous to inhabit or depend upon for a livelihood. This study starts by processing the coastal low elevated areas and the same is divided into seven different classes. These seven classes are divided into the ranges like, 0 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 4, 4.1 to 5, 5.1 to 6, and 6.1 to 10 feet respectively. The digital elevation models (DEMs) are used to get the elevation data by class wise using Geographic Information System (GIS) techniques. Further the study continued to examine all other associated geo-spatial data and revealed that the states/union territories such as West Bengal (46), Tamil Nadu (41), Odisha (34), Andhra Pradesh (32), Gujarat (30), Kerala (30), and Andaman and Nicobar islands (25), comprise the majority of cities and villages situated in low elevated areas. The study's findings and analysis are undoubtedly useful for organizing, managing, caring for, and saving the lives of those who are living in the low-lying coastal areas.
According to NOAA 2022 SLR (Sea Level Rise) technical report, Sea level along the U.S. coastline is projected to rise, on average, 10 - 12 inches (0.25 - 0.30 meters) in the next 30 years (2020 - 2050), which will be as much as the rise measured over the last 100 years (1920 - 2020). Sea level rise will vary regionally along U.S. coasts because of changes in both land and ocean height (Sweet, Hamlington et al., 2022; U.S. National Science Foundation, 2010).
Sea levels in the Indian Ocean are rising unevenly, endangering islands and coastal communities. Figure 1 illustrates how sea-level rise is most pronounced around the Arabian Sea, Bay of Bengal, Sri Lanka, Sumatra, and Java's coastlines. The seas off Sumatra, Java, Borneo, and New Guinea, as well as the equator south of India, comprise the Indo-Pacific warm pool, which stretches about halfway around the world and enters the central Pacific Ocean. There is not another open ocean on Earth with waters as warm as those in the warm pool. The temperature of the surrounding regions is greatly influenced by the warm pool since the waters are hot enough to propel heat and moisture up into the atmosphere. (Gamal, Rohmah et al., 2024; U.S. National Science Foundation, 2010).
Indian coast is a geo-cultural region in the Indian subcontinent that covers the entire coastline of India which is having about 7516.6 km length. Indian coastline cover from the south west Indian coastline along the Arabian sea from the coastline of the Gulf of Kutch in its westernmost corner and stretches across the Gulf of Khambhat, and through the Salsette Island of Mumbai along the Konkan and southwards across the Raigad district region and through Kanara and further down through Mangalore and along the Malabar through Cape Comorin in the southernmost region of South India with coastline along the Indian Ocean and through the Coromandal Coast or Cholamandalam. The coastline on the South Eastern part of the Indian Subcontinent along the Bay of Bengal through the Utkala Kalinga region extends until the easternmost Corner of shoreline near the Sunderbans in Coastal East India. There are many beaches and springs here, as well as beautiful sea and oceans like the Arabian Sea (Saravanan, Jennifer et al., 2018; Wikipedia, 2023).
Climate change related Sea Level Rise (SLR) increases the vulnerability of coastal ecosystems by posing threat to many coastal villages/cities, urban centers and coastal population in developed as well as in developing countries (NASA, 2022; Senapati and Gupta, 2014). Indian coastal regions have often been affected by frequent climate-induced natural disasters such as cyclones, floods, droughts and other related hazards in recent decades (Kantamaneni, Panneer et al., 2022; Sharma and Khan, 2023). Therefore an attempt is made in this paper to extract the state wise low elevated areas which are very close to coast and are not safe to reside there anymore (Basak, Das et al., 2021; Rehman, Sahana et al., 2021; Sonak, Pangam et al., 2008).
The sea level rise and flooding are two consequences of climate change that residential areas in low-elevation coastal zones are particularly susceptible to. The low-elevation coastal zones are home to about 11% of the world's population and about 55.2 million people in India living in low-lying coastal urban centers and those living in poverty there are particularly vulnerable to the effects of climate change. Other coastal hazards that impact low-elevation coastal zones include storm surges, coastal erosion, and saltwater intrusion. Therefore this study aims to learn more about and comprehend the elevated areas of India's coastal states and union territories by extracting and analyzing the seven types of low elevated areas (elevation ranges: 0 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 4, 4.1 to 5, 5.1 to 6, and 6.1 to 10 feet) of Indian coastal states and union territories, extract and count the number of cities and villages which are located in seven classified low-elevation coastal states and union territories and finally identify and discuss the critical cities and villages that are no longer safe to live in or rely on for survival and are situated in extremely low, elevated places of seacoast. The present study is limited to Indian coastal states and the details of the Indian coastal states and union territories and methodology used in this study is discussed in detail in the next Materials and Methods section (Prusty and Farooq, 2020; Rudiarto and Pamungkas, 2020; Yuliastuti, 2023).
By the end of 2024, India's population is predicted to surpass 1.5 billion, and making it the most populous nation in the world for the rest of the century. India's coastal population is around 171 million people, which is about 14.2% of the country's total population. The coastline of India comprises of nine coastal states, two union territories (UT) and two island territories stretching over Arabian sea and Bay of Bengal. Gujarat, Maharashtra, Goa, Karnataka, Kerala states and Daman and Diu union territory are located on the western coast of India while West Bengal, Orissa, Andhra Pradesh, Pondicherry and Tamil Nadu are located on the eastern side of Indian coast as shown in Figure 2. With a length of roughly 7,516.6 kilometers, India's coastline makes up less than 0.25% of the global coastline. India's low-lying, heavily populated coastal areas are the sites of numerous economic pursuits, including as mining, fishing, tourism, and oil and gas (Kodge, 2023; Kurniati, Widjajanti et al., 2024).
The union territories Diu Daman and Lakshadweep are not included in this study due to unavailability of proper data sets or maps.
To achieve the objectives of this study, the following methodology is used.
The study starts with processing primary data such as Digital Elevation Models (DEMs) data, base maps of coastal states/UTs, cities/villages data of coastal states/UTs and the Indian coastline map in the current investigation. The next step is to extract seven classes’ of low elevated areas (elevation ranges: 0 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 4, 4.1 to 5, 5.1 to 6, and 6.1 to 10 feet) which are close to seacoast and polygonize them for next geo-spatial data processing purposes. Once we get the region of interest (seven classes’ areas) then we can find how many numbers of cities/villages are falling within the extracted low elevated area classes. The step by step processing of this study is shown in Figure 3.
Subsequently, areas in seven classes—elevations ranging from 0 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 4, 4.1 to 5, 5.1 to 6, and 6.1 to 10 feet—are extracted. Figure 4 displays the seven distinct elevation classes together with their corresponding color codes.
All the geographical maps and charts which are presented and discussed in this study are showcased as per the Figure 4 classes and their associated colour codes for better understanding.
The software tools like, QGIS and MATLAB are used for extracting, analyzing and visualizing of geo-spatial and numeric data/values.
After extracting the required patterns from the processed datasets, the results of class wise and state wise low elevated areas, the cities/villages located in those low elevated areas/classes are generated in the form of charts and maps. The detailed discussions on the generated results are made available in the next section 3.
After successful completion of the above discussed list of processes, following are the findings of this study and the same are discussed here.
As seen in above Figure 5, the state of Gujarat has the highest (10421 km2) concentration of class-1 (dark-blue colored) low elevated areas followed by the state of Odisha (3366 km2), Andhra Pradesh (3048 kmk2), West Bengal (2831 km2), Tamilanadu (2132 km2) and Andaman and Nicobar islands (1586 km2).
Here also it is found that the Gujarat state alone has the highest area of the second low elevated class-2, which is covered about 1783 km2 followed by the states/UTs like Tamilanadu (1079 km2), Andhra Pradesh (899 km2), Odisha (664 km2), and West Bengal (648 km2).
A details discussion about each individual coastal state’s/UT’s low-elevated areas with their chart and maps are as follows:
State/UT wise low elevated area classesThe findings of the state/UT wise covered low elevated area classes in square kilometers and their class wise covered area maps are shown here. Every state/UT sub-section contains their chart and a map to show their low elevated areas and their covered area in maps. The x-axes of all charts are used to show about 7 low elevated classes, and the y-axes are used to show covered low elevated area in square kilometers. The detailed discussions about each individual seacoast state/UT are as follows:
Gujarat StateThe Gujarat state is located on the western part of India and it has 1214 km long coastline and it is a longest coastline of Indian state.
According to Figure 6(a), total 10421.3 km2 area (about 5.3% of its total land) of Gujarat state is found in class-1 and is the highest among all the coastal states of India. The brown color area in Figure 6(b) is class-1 low elevated area of Gujarat state.
Further it is again found that the class-2 low elevated area is also high in Gujarat state only, which is about 1783 km2 and the same is shown in orange color in Figure 6(b).
Maharashtra StateThe Maharashtra state has total 652.6 km long coastline and it found that it contains a very low amount of low elevated areas. But the capital of Maharashtra state as well as the financial capital of India “Mumbai” is found within the class-1 and class-2 low elevated area, which is not a good signs at all as far as the rising of sea levels are concern.
The total class-1 low elevated area of Maharashtra state is about 246 km2 and class-2 is just 89 km2. The highest amount of low elevated area in Maharashtra state is class-7, and it contains about 875 km2 areas.
The details about low elevated area classes and their covered map can be seen in above Figure 7.
Goa State
The Goa state’s coastline is about 160 km long. It is found that it has 65 km2 class-1 and 22 km2 class-2 low elevated areas. The other classes’ low elevated area values are shown in Figure 8(a) and the extracted map of Goa state’s low elevated area is shown in Figure 8(b).
Karnataka State
Karnataka state is located on the southern part of India and it has 280km long coastline. The Karnataka state’s class-1 low elevated area is found about 117 km2 and class-2 is only 71 km2. The other classes’ low elevated areas can be seen in Figure 9(a) and their covered area map is shown in Figure 9(b).
Kerala StateKerala state is also located on the southern part of India and it has 569 KM long coastline. The complete western part of the Kerala state is connected with Arabian Sea shoreline.
As shown in Figure 10(a), the Kerala’s class-1 low elevated area is about 887 km2 and class-2 type is 464 km2. Most of the coastal part of Kerala state is found under the low elevated area zones and the same can been seen in the extracted map of Kerala in Figure 10(b).
Tamilanadu State
Tamilanadu state is located on southern part of India and has 910 KM long coastline connected with Bay of Bengal in the east. Much more eastern coastal part of Tamilanadu state has low elevated area and the same can been seen in Figure 11(b).
Among all low elevated area classes, total 2132 km2 area (about 1.6% area of total state’s land) is belongs to class-1 and 1089 km2 area is found under class-2. Remaining values of other low elevated classes are also shown in the above Figure 11(a).
Andhra Pradesh State
Andhra Pradesh state is also located on the southern part of India and it is has total 973 km long coastline which makes it second longest coastline state of India.
As shown in Figure 12(a), the Andhra Pradesh state’s 1.8% land i.e. 3048 km2 area is found under class-1 and 899 km2 area is in class-2 category. The other coastal parts low elevated areas of the Andhra Pradesh state can be seen in above Figure 12(a) and covered map of the same is also shown in Figure 12(b).
Odisha State
Odisha state is located on the eastern part of India which is connected to Bay of Bengal and it has total 476 km long coastline.
Odisha is the second largest container of class-1 low elevated area which is about 2.1% (3365 km2) of its total land. The class-2 has 664 km2 and class-3 is 1546 km2 low elevated area as shown in Figure 13(a). The map of class wise low elevated covered areas can be seen in above Figure 13(b).
West Bengal State
West Bengal is a state in eastern India, between the Himalayas and the Bay of Bengal and has 157 km long coastline.
Majority of the coastal part of West Bengal state is found in low elevated area. About 3.1% (2831 km2) area is found within class-1 low elevated zone and the same (brown color) is shown in Figure 14(b). The class-7 of West Bengal state has highest land i.e. 8362km2 which is the second largest after Gujarat state as shown in Figure 14(a).
Pondicherry Union Territory
Pondicherry, also known as Puducherry, is a union territory of India which is located on the southern part of the Indian Peninsula. This UT has 30.6 km long coastline.
Among 7 low elevated classes, majority of Pondicherry land found under class-1 category i.e. 173 km2 and remaining classes are having low values as shown in Figure 15(a). The geographical distribution of all types of low elevated classes of Pondicherry UT is also shown in Figure 15(b).
Andaman & Nicobar Islands Union TerritoryThe Andaman and Nicobar Islands is a union territory of India comprising 836 islands, of which only 31 are inhabited. These islands are grouped into two main clusters: the northern Andaman Islands and the southern Nicobar Islands, separated by a 150 km wide channel.
The Andaman and Nicobar Islands 1586.61 km2 area is found under the class-1 category. It is about 19.2% area of its total land is at high risk. The low elevated class wise values of Andaman and Nicobar Islands is shown in Figure 16(a) and associated extracted map is shown in Figure 16(b).
Class wise low elevated areas in coastal statesAfter state wise low elevated area analysis, this study next move to analyze the class wise low elevated area with all coastal state and UTs.
The results of class-wise low elevated regions of all Indian coastal states/UTs are shown in Figure 17. The bulk of low elevated lands across all classifications are located in Gujarat state alone, as we seen in Figure 6. Gujarat (10421 Sq. km) has the highest Class-1 (0-1 feet), or very low elevated areas, followed by Odisha (3365), Andhra Pradesh (3048), West Bengal (2831), and Tamilanadu (2132). Gujarat (1783) has the highest concentration of Class-2 (1-2 feet) low elevated lands, followed by Tamilanadu (1089), Andhra Pradesh (899), Odisha (664), and West Bengal (648).
The majority of the Class-3 (2–3 feet) low elevated areas are found in states of Gujarat (2048), Odisha (1546), Andhra Pradesh (1123), Tamilanadu (1099), and West Bengal (957). And as far as the class-4 (3–4 feet) low elevated lands are concern, the states like Gujarat (1827), West Bengal (1812), and Andhra Pradesh (1234) are high.
The next low elevated area classes like class-4, class-5, class-6 and class-7 are also high in Gujarat state only. Therefore it is a serious matter for Gujarat state to handle the livelihood and resources at observed locations. The details about how many number of villages/cities are going to get affected with this issue is discussed in detail in section 3.3.
The cities/villages of coastal state/UTs which are located on very low elevated areas of class-1 are shown in Figure 18. Majority of cities/villages are found in class-1 zone from the states of West Bengal (46), Tamil Nadu (41), Odisha (34), Andhra Pradesh (32), Gujarat (30), Kerala (30), and Andaman and Nicobar island (25) union territory.
Again the class-2 zone also has more number of cities/villages from West Bengal (41) state only followed by the states of Tamilanadu (16), Gujarat (11), Odisha(11), Andhra Pradesh(10) and Kerala (10).
According to Figure 19, it is observed that total 1071 cities/villages of India are located in low elevated areas (class-1 to class-6). Among the total 1071 cities/villages about 248 (23.15%) are found in class-1 (extremely low elevated area, 0–1 feet), 98 are in class-2 and 156 are found in class-3 zone which could be unsafe for livelihood in future.
Next this study attempted to find out the state wise cities/villages located in the all 6 classes’ low elevated areas. The Figure 20 shows the results of individual state/UT wise number of cities/villages which are found located within the respective low elevation classes (from class-1 to class-6).
The Figure 20(a) shows that, out of total 134 cities/villages of Gujarat state, 30 are located in class-1, 11 are in class-2 and 13 are in class-3. The majority of cities/villages like 36 are found in class-6 and 30 are found in class-5. The cities like Dwarka, Okha, Mandvi, Navsari, Valsad, Gulf of Khambhat, Gulf of Kachchh and Saurashtra coast are at risk.
The details of cities/villages located in low elevated areas of Maharashtra state is shown in Figure 20(b). There are total 65 cities/villages are found located in low elevated areas of Maharashtra state. Out of 65, there are 15 cities/villages are located in class-1, 3 are there in class-2, 9 are in class-3 and 13 are there in class-4 low elevated zones. The cities/villages like Mumabi, Alibag, Ganpatipule, Tarkarli and others are at high risk.
It is found that Goa state’s 27 cities/villages in low elevated area zones. Among 27, 9 are found located in class-1, 3 each in class-2 and class-3. The cities/villages like Anjuna, Arambol, Mandrem, Vasco Da Gama, Miramar and other few are at risk. The details number of cities/villages of Goa state located in low elevated zones can be seen in the Figure 20(c).
There are total 19 cities/villages found in low elevated areas of Karnataka state. Among these 6 are located in class-1, 1 is in class-2 and 4 in class-3. The details about remaining classes are shown in Figure 20(d). From this study it is also found that the cities/villages like Karwar, Gokarna, Honnawar, Manglore coast are at high risk.
Kerala’s total 91 cities/villages are found in low elevated area zones. Among those about 30 cities/villages are found located in the class-1 low elevated area only. According to Figure 20(e), the remaining 10, 16, 21, 8 and 6 cities/villages are found in class-2, class3, class4, class-5 and class-6 respectively. As per extracted results from Kerala state, it is also observed that the cities/villages like Kasaragod, Kannur, Thalaserry, Kozhikode, Kochi, Kollam, Kovalam are at high risk.
There are a total of 113 cities/villages are located in low elevated coastal area zones. Out of this majority of cities/villages like 41 (36%) are found within class-1 low elevated area. The class-2 has 16, class-3 contains 10 and 23 cities/villages are found in class-4 as shown in Figure 20(f). In Tamilanadu the cities/villages like, Colachel, Muttom, Manakudy, Kanniyakumari, Koodankulam, Manapad, Rameshwaram, Chennai are found at high risk.
Andhra Pradesh state’s total 128 cities/villages are found in low elevated coastal zones. As shown in Figure 20(h), there are 32 cities/villages found in class-1, 10 in class-2, 15 in class-3, 14 in class-4, 28 in class-5 and 29 in class-6 low elevated areas. The cities/villages like Chinna Gollepalem, Antervedi Pallipalem, Odalarevu, Kakinada, Visakhapatnam are found at high risk.
About 88 cities/villages from Odisha state are found in low elevated coastal zones. Among 88, majority of cities/villages i.e. 34 (38%) are found in class-1 and 11 are found in class-2 low elevated areas. The remaining cities/villages of Odisha state with their zones can be seen in above Figure 20(i). The cities/villages in Odisha state like Gopalpur, Puri, Kanik island, Kharasahpur, Inchudi, Jamunasul and others found at high risk.
Among all coastal states/UTs, the West Bengal state has the highest number of cities/villages i.e. 494 are located in low elevated coastal zones. As shown in Figure 20(j), there are 46 cities/villages from West Bengals state found in class-1, class-2 has 41, in class-3 73 and class-4 contains 97. In West Bengal state the cities/villages like, Digha, Mandarmani, Gangasagar, Balira, Bakkhali, Gobardhanpur, Kultali, Jharkali and few others are found at high risk.
The Pondicherry union territory is located in three different parts. Pondicherry’s total 15 cities/villages are found in low elevated coastal zones. As shown in Figure 20(g), 10 cities/villages are found in class-1, 2 are in class-2, 1 in class-4 and 2 in class-5. In this UT, the cities/villages like, Puducherry, Nallavadu, Veerampattinum, Chinna Veerampattinum, Karaikal, Mahe and few other are found at high risk.
Andaman Nicobar UT’s 31 cities/villages are found in low elevated coastal zones. As shown in Figure 20(k), 80% of cities/villages are in class-1 only and remaining 1, 3, 2 are found in class-2, class-3 and class-4 respectively. The cities/villages of this UT like, Perka, Anul, Campbel Bay, Laful, Tapiang, Lakshmanpur, Sri Vijaya Puram, Coco island and few other are found at high risk.
This study focused on low-lying elevated areas and cities/villages that will be impacted by future sea level rise issues in India's coastal states and union territories. The methodology used in this study demonstrated its efficacy by producing optimum outputs. The research carried out in this study generated significant outputs in the form of charts and geographical maps for easy and better understanding.
The outcomes of this study will be of great assistance to the local government or administrative of Indian coastal states/UTs, where the citizens dwell in low-lying areas/cities/villages. The extracted results of this study clearly show that about 5% of the Gujarat state is situated in an extremely low elevation region, where future sea level rise, tsunamis, and floods could pose a variety of problems. Next, the states like Andhra Pradesh, Odisha, West Bengal, and Tamil Nadu have extremely low elevated areas. Further it is also found that, among all states and UTs, the Andaman & Nicobar Islands has the largest percentage of low elevated area (l9.2%).
A large number of villages are located in extremely low elevation locations across the bulk of coastal states and union territories, such as Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Pondicherry, Andhra Pradesh, Odisha, and the Andaman & Nicobar Islands. In the Andaman and Nicobar Islands, about 25 of the 30 settlements are found to be located in extremely low elevation areas, making them potentially exceedingly perilous in the case of a tsunami, flood, or sea level rise in the future. There is little question that the organization, management, care, and preservation of the lives of people residing in shown low-lying coastal areas will benefit from the study's conclusions and analysis.
Additionally, it is also noted that millions of Indians reside in high-risk cities like Mumbai, Mangalore, Kochi, Chennai, and Vishakhapatnam.
The current study's restriction is that, it can extract and analyze the low elevation areas and determine how many number of cities/villages that will be impacted in the chosen coastal states and union territories of India. This study is currently unable to address how many people, infrastructure, built-up land (residential/commercial areas), transportation, and other services that would be impacted. The same can be done by recognizing, extracting, and analyzing the required patterns from high resolution LULC (Land Use and Land Cover) and remote sensing imageries of India's coastal states and union territories. This work will be extended to overcome the aforementioned constraint in future.
This is a single authored paper; therefore all the work presented in this study is carried out by me only.
The author declares that he has no conflicts of interest regarding publication of the paper.
I am grateful to BHUVAN (ISRO), NRSC Hyderabad, and Survey of India for providing DEMs, Remote Sensing Images and base maps of my study areas and similarly, I am also thankful to all who have directly or indirectly helped me to complete this work.
