Introduction:

India and Bangladesh share a unique bond and a special relationship rooted in a common cultural heritage, shared principles and values and forged by common aspirations and sacrifices of its peoples. India is committed to carry forward the mission of strengthening the historic bonds and impart a vision for the future that is durable and sustainable and conducive for the collective prosperity of the region. 
Bangladesh's geopolitical importance for India is due to three factors. First, Bangladesh’s location is a strategic wedge between mainland India and Northeastern seven states of the Indian Union. Each of these states is land-locked and has shorter route to the sea through Bangladesh. Currently, Kolkata port is used by these states for both domestic and imported cargo.  Bangladesh is a natural pillar of “Look East Policy”. A friendly Bangladesh that ensures no anti-India terror or insurgent activities can be carried out from its soil unlike in the past will substantially assist India in handling security problems in some of its restive north-east States. Importantly, a ‘neutral’ Bangladesh also ensures containment of an assertive China in this region, including along the strategic sea-lanes of the Bay of Bengal.
Further the navigable rivers in India's Northeast that could connect West Bengal or Orissa ports pass through Bangladesh. The only entry to and exit from the Northeastern region of India is through the Shiliguri Corridor that is close to the Chinese border and within striking distance of Bangladesh. The Shiliguri Corridor is the most sensitive 'choke point' for the Indian Union.

But unfortunately, there exist many contentious issues between the two countries. The issues are discussed as below:

a) Water dispute

India and Bangladesh share 54 trans-boundary rivers, big and small. In 1996, the sharing of the Ganga waters was successfully agreed upon between the two nations. However, the major area of dispute has been India’s construction and operation of the Farakka Barrage. The aim of construction of the Farakka Barrage was to increase the lean period flow of the Bhagirathi-Hooghly branch of Ganga to increase the water depth at the Kolkota port which was threatened by siltation. As irrigation withdrawals increased in Bangladesh, dispute arose between India and Bangladesh over the sharing of the lean season flow at Farakka. The inadequacy of water during the lean season to meet the assessed demands in the two countries is the root cause of the conflict.
The Bangladesh government feels that the reduction in flow caused damage to agriculture, industry and ecology in the basin in Bangladesh. Because of the inability of the concerned governments to come to any lasting agreement over the last few decades on sharing the river water, this problem has grown and now it is also viewed as a case of upstream-downstream dispute.
The other reason for water dispute is Teesta River – which has its source in Sikkim – flows through the northern part of West Bengal in India before entering Bangladesh, where after crosssing through about 45km of irrigable land, merges with the Brahmaputra River (or Jamuna when it enters Bangladesh). In 1983, an ad-hoc water sharing agreement was reached between India and Bangladesh, whereby both countries were allocated 39% and 36% of the water flow respectively. The new bilateral treaty expands upon this agreement by proposing an equal allocation of the Teesta River. However, the deal fell through when the then newly elected Chief Minister of West Bengal, Ms. Mamata Banerjee, refused to approve the treaty, fearing that the loss of higher volume of water to the lower riparian would cause problems in the northern region of state, especially during drier months.
Construction of the Tipaimukh Dam is another contentious issue between India and Bangladesh. Tipaimukh Dam is a hydel power project proposed on the river Barak in Manipur. Bangladesh's objection is that it would have adverse ecological effects in its eastern Sylhet district. In spite of India's reiteration that no dam would be constructed overlooking Bangladesh's objections, the controversy is far from over.
The popular arguments in Bangladesh against the Tipaimukh project are:

• India should not decide what is good for people of Bangladesh without taking them into confidence;

• No study has been undertaken in Bangladesh to assess the impact of the ecosystems that exist and depend on the natural flow of the water in Surma-Kusiyara-Meghna and their tributaries.

India and Bangladesh have agreed on a joint study group to examine the points raised by Bangladesh. 

b) Boundary Dispute

India’s land border with Bangladesh as per the Ministry of Defence is 4351 km. running through five states, viz., West Bengal (2217kms), Assam (262 kms), Meghalaya (443kms), Tripura (856 kms) and Mizoram (318 kms), including nearly 781 kms of riverine border. The border traverses through 25 districts.
The border is used as a route for smuggling livestock, food items, medicines and drugs from India to Bangladesh. Moreover, illegal immigrants from Bangladesh cross the border to India in search of improving their lives. Because of a large number of illegal immigrants crossing from Bangladesh into India, a controversial shoot-on-sight policy has been enforced by the Indian border patrols. This policy was initiated with reports of violence between the illegal migrants and Indian soldiers. The border has also witnessed occasional skirmishes between the Indian Border Security Force and the Border Guards Bangladesh, most notably in 2001.
The killing of Bangladeshi nationals by Border Security Force (BSF) has become a major irritant between the two countries in the recent past. It has evoked strong public sentiments in Bangladesh. According to a report of Bangladesh Human Rights Watch organization Odhikar, BSF has, from January 1, 2001 to March 31, 2012, killed 907 Bangladeshis. Bangladesh wants no time lost in stopping these killings.
Further the Agreement on the demarcation of Land Boundary between Bangladesh and India and related matters had been signed in May 1974 between the two great statesmen, Bangabandhu Sheikh Mujibur Rahman, and Smt. Indira Gandhi. This comprehensive agreement was intended to resolve all lingering and vexing problems that history had bequeathed on the two nations.  But it has not full filled by both Governments.

During the State visit of the Prime Minister to Bangladesh in September 2011, a "Protocol to the Agreement between the Government of India and the Government of Bangladesh Concerning the Demarcation of the Land Boundary Between India and Bangladesh and Related Matters (LBA)” was signed. It settles the long outstanding land boundary issues related to un-demarcated segment of 6.1 Kms; territories in adverse possession; and exchange of enclaves. The Cabinet has, on 13 February 2013, approved the draft of a Constitution (Amendment) Bill for implementing the India-Bangladesh Land Boundary Agreement (LBA) 1974 and the Protocol to LBA signed in 2011. The Protocol envisages that 111 Indian Enclaves in Bangladesh and 51 Bangladesh Enclaves in India, as per the jointly verified cadastral enclave maps, shall be exchanged. As per Article 3 of the LBA 1974, when the Enclaves are transferred, people living in these areas shall be given the right of staying on where they are as nationals of the State to which the areas are transferred.
The delay in implementation of the land boundary agreement signed during the Indian Prime Minister's visit has increased the differences. The Bangladesh Parliament has ratified the agreement, but it awaits ratification by the Indian Parliament. Bangladesh is urging India to take necessary steps at the earliest to make it functional. The reason for the parliamentary delay is the reservation expressed by some sections, mainly people living on the border, who complain that they had not been consulted before signing the treaty. They also argue that implementation of the treaty would have adverse impact on their lives. 

Maritime border 

While  Bangladesh,  having  concave coastlines,  delimits  its  sea  border southward  from  the  edge  of  its  land boundary,  India  stretches  its  claim southeast  wards,  covering  around thousands  of  miles  in  the  Bay  of  Bengal. Due  to  competing  claims  of  the  two countries,  delimitation  of  the  sea boundary  and  determining  Bangladesh’s exclusive  economic  zones  have  remained unresolved.  Moreover, in terms  of determining the continental shelf, the presence of the Andamans and Nicobar Islands puts India, in a  favourable position. 

Territorial Waters 

The issue of demarcating territorial waters led to serious differences between the two countries. Questions  of ownership over a new born island known as South Talpatty in Bangladesh and New Moore/ Purbasha in  India  spotted  by  a satellite picture in 1975 in  the estuary of Haribhanga  River  on  the  border  of  the two  countries  has  been  a  source  of contention since its discovery. In order to settle the above dispute  Bangladesh proposed sending a joint Indo-Bangladesh team to determine the flow of channels of the  river  on  the  basis  of  existing International  Law  of  the  Sea.  But  the Indian  counterpart  sent  forces  to establish  claims  by  stationing  naval troops on  the island in 1981. After initial resentment  by  Bangladesh,  India  agreed to resolve the issue through negotiations. Till  now  the  sovereignty  over  the  island nation  remains      undecided,  and  recent reports  of  the  press  and  media  suggests that  Bangladesh  views India with suspicion in its activities over the disputed piece of landmass on the breast of an international water.  

c) Illegal Migration

Illegal migration is one of the bones of the contention of these two countries, Since the 1971 war of independence that created the state of Bangladesh, millions of Bangladeshi immigrants (the vast majority of them illegal) have poured into neighbouring India. While the Indian government has tried to deport some of these immigrants, the sheer number of them, as well as the porous border between the two countries, has made such an enterprise impossible. It is difficult to assess how many illegal immigrants are currently residing in India. Consider that in 1971, during the civil war in neighboring East Pakistan (the former name of Bangladesh), at least 10-million Bangladeshis poured into West Bengal in India
Illegal migration appears in the eastern and north-eastern parts of the country from neighbouring Bangladesh, threat to India’s internal security, from Bangladesh  is impacted on communal, political, social and economic tensions and conflicts in several areas of the northeast of India. The most affected states are West Bengal, Assam, Megalaya, Nagaland, Bihar, and Tripura, although migrants “have spread too far off states like Tamil Nadu, Maharashtra, Gujarat, Rajasthan and Delhi.”  Although the exact figure is not known, it is estimated that there are about 15-20 million Bangladeshis staying illegally in India.  
The National Investigation Agency has found links with Pakistan in rackets engaged in printing and smuggling fake currency into India. NIA sources said fake currency was now being smuggled into the border with Bangladesh has gaps at some points and immigrants cross into India on foot through the breaks in the fence. Some also swim across rivers on the border to reach India. The National Investigation Agency has found links with Pakistan in rackets India through its porous border with Bangladesh. Malda district in West Bengal is a key transit point for counterfeiters.   Once they reach India, immigrants obtain fake documents through local agents.  Political leaders in parts of West Bengal were also involved in endorsing fake documents such as ration cards for illegal immigrants. 
This unfettered illegal migration impacts on national security and socio-economic stability. Intelligence inputs indicate that the Inter Service Intelligence Agency (ISI) of Pakistan is utilizing these migrants as conduits to ferry in terrorists and arms into India. Counterfeit Indian currency with its origins in Bangladesh has flooded border areas, crippling in these parts.
Vote bank politics in Assam is the one of obstacle to control illegal migration from Bangladesh, led to communal violence between indigenous Bodos and Muslims (migrants from Bangladesh) in 2012.  
The illegal Bangladeshi immigrants have not only changed the demography and disturbed the ecology of the north-east but have also encouraged them to exercise their political rights in India as citizens. It has been one of the key reasons for the rise of insurgent groups in the north-east as some of the insurgent groups like Assam Gana Sangram Parishad started, and got support of the masses, because of the issue of illegal immigration from Bangladesh. At the same time the immigration laws (Illegal Migrants [Determined by Tribunal] (IMDT) Act 1983) followed in Assam has aided illegal immigrants’ settling in the north-east easy.

d) Security concerns 

Insurgency has been playing the role in straining relations of India with Bangladesh. Northeast India has been facing insurgency since 1956 due to feelings of ethnic separatism among its inhabitants. ISI is operating from Bangladesh, supporting the insurgents in the North east India. National Liberation of Tripura (NLFT), Liberation Front of Assam(ULFA) and National Democratic Front of  Bodoland (NDFM) are major insurgent groups in Northeast India. There are some rumours that ULFA has several lucrative income generating Projects in Bangladesh to sustain its insurgency activities in India.

Drug Trafficking 

Bangladesh is increasingly being used as a transit point by drug dealers and the drug mafia,  which  dispatches  heroin  and opium  from  Burma,  and  other  countries of  the  golden  triangle,  to  different destinations.  As  a  result,  Bangladesh’s Department  of  Narcotics  Control  has  come  under  the  scanner  several  times  and  invited  criticism. Bangladesh  has  become the  prime  transit  route  for  trafficking heroin  to  Europe  from  Southeast Asia, according  to  a  report  from  the International  Narcotics  Control  Board  (INCB)  2007  annual  report .  INCB  notes  that  the  most  common methods and routes for smuggling heroin into  Bangladesh  are  by  courier  from Pakistan,  commercial  vehicles  and  trains from India, and via sea through the Bay of Bengal  or  overland  by  truck  or  public transport from Burma.

e) Trade and Investment

Bangladesh is an important trading partner for India. The two-way trade in FY 2011-2012 was US$5.242 billion with India's exports to Bangladesh accounting for US$4.743 billion and imports US$0.498 million. 
The trade deficit with India is frequently highlighted by Bangladesh as a major contentious issue. Trade deficit for Bangladesh is more than $4 billion.  For long, Bangladesh has been urging India to reduce this gap by lifting the tariff barriers as they were a major impediment to the growth of Bangladesh's exports to India. Responding to Bangladesh's concern, in November 2011, India granted duty free access to all products, except 10 tobacco and liquor items from Bangladesh which amounts 30% of Bangladesh export. As much as 98 per cent of Bangladesh products now enjoy zero duty benefits in the Indian market. Bangladesh's exports to India are expected to cross $1 billion in 2012.
However, Bangladesh is now urging India to remove all non-tariff barriers (NBTs) as it views NTBs as the major obstacles to its export growth. Some of these barriers are: laboratory test for every consignment of food products, cosmetics, and leather and textile products; delay in getting test results; imposition of state tax; packaging requirement, anti-dumping and countervailing duties; inadequate infrastructure facilities such as warehousing, trans-shipment yard, parking yard and; connecting roads at land customs stations of India. To encourage exports from Bangladesh, India must move proactively to provide facilities of customs and testing at the border check posts.
Besides, removal of non-tariff barriers should be accompanied by tariff reforms since the opportunity cost of non-tariff barriers is very high. A Consumer Unity & Trust Society (CUTS) International report says: “In 2010, value of unexplored market was more than 48 per cent of total value of India- Bangladesh trade and potential saving, which is a proxy for cost of non-tariff barriers, is more than seven per cent of total value of Indo-Bangla trade”.
India is also encouraging investments in Bangladesh. In this regard, a Bilateral Investment Promotion and Protection Agreement have been signed between the two countries. The agreement is expected to increase Indian investment in Bangladesh. 

f) Transit

India has been urging Bangladesh to provide rail and road transit to connect with its north-eastern states. Technically speaking, the issue of transit was resolved in 1972 when both sides agreed on a mutually beneficial arrangement for the use of their waterways, railways and roadways for commerce between two countries and for passage of goods to places in one country through the territory of the other. Inland water transit has been functional, but the rail and road transit is still waiting to be operational.
Bangladesh's initial reluctance to granting India rail and road transit was on the grounds that transit facility once given was difficult to take back and such a facility may encourage terrorism and insurgency.
Other concerns included damage to the roads and bridges in Bangladesh by the increased traffic flow from the Indian side.
The reason for delay was that Bangladesh's infrastructure was not yet prepared to take the load of the increased traffic that will follow with the granting of transit to India. Addressing Bangladesh's concern, India provided a credit line of $1billion to Bangladesh for development of infrastructure projects. But the credit line could not be used to its potential because of the strict conditions India imposed, to the effect that 85 per cent of the raw materials for the road projects has to be procured from India, on the ground that it produces all the materials necessary. Bangladesh has countered by claiming it too has the necessary raw materials. It could earn $44 million per annum for first five years if it grants transit to India. From the sixth year, earnings would be around $500 million, which could rise to $1 billion.  Transit would not only boost connectivity between the two countries, but also offer opportunities for regional connectivity and help Bangladesh develop Chittagong port into a regional hub.
The  Chittagong  port  can  become  a modern  busy  port  like  Singapore  and  China  serving  the  SAARC  countries.  Huge  foreign  investment  may  be attracted by Bangladesh and  finally, a throbbing  service  sector like banks, insurance, hotels, rest houses, petrol pumps etc. may develop around the Transcontinental roads and railways.  There  is  an  estimate  of  direct economic  gain  from  transit  fees.  It ranges from  500  crore  taka  to  4,666 crore taka.  The  mutual  transit will  also give Bangladesh  a  much  shorter  route  to China and an initiative to link Chinese province  of  Yunan with  Seven Sisters of  India,  Myanmar,  Thailand  and Bangladesh. 

Conclusion

India-Bangladesh relations have more than an academic strategic content. In the long run, India’s national interests primarily lie towards and beyond its eastern flanks to South East Asia and the new geographical and strategic construct namely Indo-Pacific Asia. India thus needs to strengthen the various regional groupings in this region like the ASEAN and the BIMSTEC (Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation). Importantly, they should work together to resolve all the issues.  

India and Bangladesh share a unique bond and a special relationship rooted in a common cultural heritage, shared principles and values and forged by common aspirations and sacrifices of its peoples. India is committed to carry forward the mission of strengthening the historic bonds and impart a vision for the future that is durable and sustainable and conducive for the collective prosperity of the region. 
Bangladesh's geopolitical importance for India is due to three factors. First, Bangladesh’s location is a strategic wedge between mainland India and Northeastern seven states of the Indian Union. Each of these states is land-locked and has shorter route to the sea through Bangladesh. Currently, Kolkata port is used by these states for both domestic and imported cargo.  Bangladesh is a natural pillar of “Look East Policy”. A friendly Bangladesh that ensures no anti-India terror or insurgent activities can be carried out from its soil unlike in the past will substantially assist India in handling security problems in some of its restive north-east States. Importantly, a ‘neutral’ Bangladesh also ensures containment of an assertive China in this region, including along the strategic sea-lanes of the Bay of Bengal.
Further the navigable rivers in India's Northeast that could connect West Bengal or Orissa ports pass through Bangladesh. The only entry to and exit from the Northeastern region of India is through the Shiliguri Corridor that is close to the Chinese border and within striking distance of Bangladesh. The Shiliguri Corridor is the most sensitive 'choke point' for the Indian Union.

But unfortunately, there exist many contentious issues between the two countries. The issues are discussed as below:

a) Water dispute

India and Bangladesh share 54 trans-boundary rivers, big and small. In 1996, the sharing of the Ganga waters was successfully agreed upon between the two nations. However, the major area of dispute has been India’s construction and operation of the Farakka Barrage. The aim of construction of the Farakka Barrage was to increase the lean period flow of the Bhagirathi-Hooghly branch of Ganga to increase the water depth at the Kolkota port which was threatened by siltation. As irrigation withdrawals increased in Bangladesh, dispute arose between India and Bangladesh over the sharing of the lean season flow at Farakka. The inadequacy of water during the lean season to meet the assessed demands in the two countries is the root cause of the conflict.
The Bangladesh government feels that the reduction in flow caused damage to agriculture, industry and ecology in the basin in Bangladesh. Because of the inability of the concerned governments to come to any lasting agreement over the last few decades on sharing the river water, this problem has grown and now it is also viewed as a case of upstream-downstream dispute.
The other reason for water dispute is Teesta River – which has its source in Sikkim – flows through the northern part of West Bengal in India before entering Bangladesh, where after crosssing through about 45km of irrigable land, merges with the Brahmaputra River (or Jamuna when it enters Bangladesh). In 1983, an ad-hoc water sharing agreement was reached between India and Bangladesh, whereby both countries were allocated 39% and 36% of the water flow respectively. The new bilateral treaty expands upon this agreement by proposing an equal allocation of the Teesta River. However, the deal fell through when the then newly elected Chief Minister of West Bengal, Ms. Mamata Banerjee, refused to approve the treaty, fearing that the loss of higher volume of water to the lower riparian would cause problems in the northern region of state, especially during drier months.
Construction of the Tipaimukh Dam is another contentious issue between India and Bangladesh. Tipaimukh Dam is a hydel power project proposed on the river Barak in Manipur. Bangladesh's objection is that it would have adverse ecological effects in its eastern Sylhet district. In spite of India's reiteration that no dam would be constructed overlooking Bangladesh's objections, the controversy is far from over.
The popular arguments in Bangladesh against the Tipaimukh project are:

• India should not decide what is good for people of Bangladesh without taking them into confidence;

• No study has been undertaken in Bangladesh to assess the impact of the ecosystems that exist and depend on the natural flow of the water in Surma-Kusiyara-Meghna and their tributaries.

India and Bangladesh have agreed on a joint study group to examine the points raised by Bangladesh. 

b) Boundary Dispute

India’s land border with Bangladesh as per the Ministry of Defence is 4351 km. running through five states, viz., West Bengal (2217kms), Assam (262 kms), Meghalaya (443kms), Tripura (856 kms) and Mizoram (318 kms), including nearly 781 kms of riverine border. The border traverses through 25 districts.
The border is used as a route for smuggling livestock, food items, medicines and drugs from India to Bangladesh. Moreover, illegal immigrants from Bangladesh cross the border to India in search of improving their lives. Because of a large number of illegal immigrants crossing from Bangladesh into India, a controversial shoot-on-sight policy has been enforced by the Indian border patrols. This policy was initiated with reports of violence between the illegal migrants and Indian soldiers. The border has also witnessed occasional skirmishes between the Indian Border Security Force and the Border Guards Bangladesh, most notably in 2001.
The killing of Bangladeshi nationals by Border Security Force (BSF) has become a major irritant between the two countries in the recent past. It has evoked strong public sentiments in Bangladesh. According to a report of Bangladesh Human Rights Watch organization Odhikar, BSF has, from January 1, 2001 to March 31, 2012, killed 907 Bangladeshis. Bangladesh wants no time lost in stopping these killings.
Further the Agreement on the demarcation of Land Boundary between Bangladesh and India and related matters had been signed in May 1974 between the two great statesmen, Bangabandhu Sheikh Mujibur Rahman, and Smt. Indira Gandhi. This comprehensive agreement was intended to resolve all lingering and vexing problems that history had bequeathed on the two nations.  But it has not full filled by both Governments.

During the State visit of the Prime Minister to Bangladesh in September 2011, a "Protocol to the Agreement between the Government of India and the Government of Bangladesh Concerning the Demarcation of the Land Boundary Between India and Bangladesh and Related Matters (LBA)” was signed. It settles the long outstanding land boundary issues related to un-demarcated segment of 6.1 Kms; territories in adverse possession; and exchange of enclaves. The Cabinet has, on 13 February 2013, approved the draft of a Constitution (Amendment) Bill for implementing the India-Bangladesh Land Boundary Agreement (LBA) 1974 and the Protocol to LBA signed in 2011. The Protocol envisages that 111 Indian Enclaves in Bangladesh and 51 Bangladesh Enclaves in India, as per the jointly verified cadastral enclave maps, shall be exchanged. As per Article 3 of the LBA 1974, when the Enclaves are transferred, people living in these areas shall be given the right of staying on where they are as nationals of the State to which the areas are transferred.
The delay in implementation of the land boundary agreement signed during the Indian Prime Minister's visit has increased the differences. The Bangladesh Parliament has ratified the agreement, but it awaits ratification by the Indian Parliament. Bangladesh is urging India to take necessary steps at the earliest to make it functional. The reason for the parliamentary delay is the reservation expressed by some sections, mainly people living on the border, who complain that they had not been consulted before signing the treaty. They also argue that implementation of the treaty would have adverse impact on their lives. 

Maritime border 

While  Bangladesh,  having  concave coastlines,  delimits  its  sea  border southward  from  the  edge  of  its  land boundary,  India  stretches  its  claim southeast  wards,  covering  around thousands  of  miles  in  the  Bay  of  Bengal. Due  to  competing  claims  of  the  two countries,  delimitation  of  the  sea boundary  and  determining  Bangladesh’s exclusive  economic  zones  have  remained unresolved.  Moreover, in terms  of determining the continental shelf, the presence of the Andamans and Nicobar Islands puts India, in a  favourable position. 

Territorial Waters 

The issue of demarcating territorial waters led to serious differences between the two countries. Questions  of ownership over a new born island known as South Talpatty in Bangladesh and New Moore/ Purbasha in  India  spotted  by  a satellite picture in 1975 in  the estuary of Haribhanga  River  on  the  border  of  the two  countries  has  been  a  source  of contention since its discovery. In order to settle the above dispute  Bangladesh proposed sending a joint Indo-Bangladesh team to determine the flow of channels of the  river  on  the  basis  of  existing International  Law  of  the  Sea.  But  the Indian  counterpart  sent  forces  to establish  claims  by  stationing  naval troops on  the island in 1981. After initial resentment  by  Bangladesh,  India  agreed to resolve the issue through negotiations. Till  now  the  sovereignty  over  the  island nation  remains      undecided,  and  recent reports  of  the  press  and  media  suggests that  Bangladesh  views India with suspicion in its activities over the disputed piece of landmass on the breast of an international water.  

c) Illegal Migration

Illegal migration is one of the bones of the contention of these two countries, Since the 1971 war of independence that created the state of Bangladesh, millions of Bangladeshi immigrants (the vast majority of them illegal) have poured into neighbouring India. While the Indian government has tried to deport some of these immigrants, the sheer number of them, as well as the porous border between the two countries, has made such an enterprise impossible. It is difficult to assess how many illegal immigrants are currently residing in India. Consider that in 1971, during the civil war in neighboring East Pakistan (the former name of Bangladesh), at least 10-million Bangladeshis poured into West Bengal in India
Illegal migration appears in the eastern and north-eastern parts of the country from neighbouring Bangladesh, threat to India’s internal security, from Bangladesh  is impacted on communal, political, social and economic tensions and conflicts in several areas of the northeast of India. The most affected states are West Bengal, Assam, Megalaya, Nagaland, Bihar, and Tripura, although migrants “have spread too far off states like Tamil Nadu, Maharashtra, Gujarat, Rajasthan and Delhi.”  Although the exact figure is not known, it is estimated that there are about 15-20 million Bangladeshis staying illegally in India.  
The National Investigation Agency has found links with Pakistan in rackets engaged in printing and smuggling fake currency into India. NIA sources said fake currency was now being smuggled into the border with Bangladesh has gaps at some points and immigrants cross into India on foot through the breaks in the fence. Some also swim across rivers on the border to reach India. The National Investigation Agency has found links with Pakistan in rackets India through its porous border with Bangladesh. Malda district in West Bengal is a key transit point for counterfeiters.   Once they reach India, immigrants obtain fake documents through local agents.  Political leaders in parts of West Bengal were also involved in endorsing fake documents such as ration cards for illegal immigrants. 
This unfettered illegal migration impacts on national security and socio-economic stability. Intelligence inputs indicate that the Inter Service Intelligence Agency (ISI) of Pakistan is utilizing these migrants as conduits to ferry in terrorists and arms into India. Counterfeit Indian currency with its origins in Bangladesh has flooded border areas, crippling in these parts.
Vote bank politics in Assam is the one of obstacle to control illegal migration from Bangladesh, led to communal violence between indigenous Bodos and Muslims (migrants from Bangladesh) in 2012.  
The illegal Bangladeshi immigrants have not only changed the demography and disturbed the ecology of the north-east but have also encouraged them to exercise their political rights in India as citizens. It has been one of the key reasons for the rise of insurgent groups in the north-east as some of the insurgent groups like Assam Gana Sangram Parishad started, and got support of the masses, because of the issue of illegal immigration from Bangladesh. At the same time the immigration laws (Illegal Migrants [Determined by Tribunal] (IMDT) Act 1983) followed in Assam has aided illegal immigrants’ settling in the north-east easy.

d) Security concerns 

Insurgency has been playing the role in straining relations of India with Bangladesh. Northeast India has been facing insurgency since 1956 due to feelings of ethnic separatism among its inhabitants. ISI is operating from Bangladesh, supporting the insurgents in the North east India. National Liberation of Tripura (NLFT), Liberation Front of Assam(ULFA) and National Democratic Front of  Bodoland (NDFM) are major insurgent groups in Northeast India. There are some rumours that ULFA has several lucrative income generating Projects in Bangladesh to sustain its insurgency activities in India.

Drug Trafficking 

Bangladesh is increasingly being used as a transit point by drug dealers and the drug mafia,  which  dispatches  heroin  and opium  from  Burma,  and  other  countries of  the  golden  triangle,  to  different destinations.  As  a  result,  Bangladesh’s Department  of  Narcotics  Control  has  come  under  the  scanner  several  times  and  invited  criticism. Bangladesh  has  become the  prime  transit  route  for  trafficking heroin  to  Europe  from  Southeast Asia, according  to  a  report  from  the International  Narcotics  Control  Board  (INCB)  2007  annual  report .  INCB  notes  that  the  most  common methods and routes for smuggling heroin into  Bangladesh  are  by  courier  from Pakistan,  commercial  vehicles  and  trains from India, and via sea through the Bay of Bengal  or  overland  by  truck  or  public transport from Burma.

e) Trade and Investment

Bangladesh is an important trading partner for India. The two-way trade in FY 2011-2012 was US$5.242 billion with India's exports to Bangladesh accounting for US$4.743 billion and imports US$0.498 million. 
The trade deficit with India is frequently highlighted by Bangladesh as a major contentious issue. Trade deficit for Bangladesh is more than $4 billion.  For long, Bangladesh has been urging India to reduce this gap by lifting the tariff barriers as they were a major impediment to the growth of Bangladesh's exports to India. Responding to Bangladesh's concern, in November 2011, India granted duty free access to all products, except 10 tobacco and liquor items from Bangladesh which amounts 30% of Bangladesh export. As much as 98 per cent of Bangladesh products now enjoy zero duty benefits in the Indian market. Bangladesh's exports to India are expected to cross $1 billion in 2012.
However, Bangladesh is now urging India to remove all non-tariff barriers (NBTs) as it views NTBs as the major obstacles to its export growth. Some of these barriers are: laboratory test for every consignment of food products, cosmetics, and leather and textile products; delay in getting test results; imposition of state tax; packaging requirement, anti-dumping and countervailing duties; inadequate infrastructure facilities such as warehousing, trans-shipment yard, parking yard and; connecting roads at land customs stations of India. To encourage exports from Bangladesh, India must move proactively to provide facilities of customs and testing at the border check posts.
Besides, removal of non-tariff barriers should be accompanied by tariff reforms since the opportunity cost of non-tariff barriers is very high. A Consumer Unity & Trust Society (CUTS) International report says: “In 2010, value of unexplored market was more than 48 per cent of total value of India- Bangladesh trade and potential saving, which is a proxy for cost of non-tariff barriers, is more than seven per cent of total value of Indo-Bangla trade”.
India is also encouraging investments in Bangladesh. In this regard, a Bilateral Investment Promotion and Protection Agreement have been signed between the two countries. The agreement is expected to increase Indian investment in Bangladesh. 

f) Transit

India has been urging Bangladesh to provide rail and road transit to connect with its north-eastern states. Technically speaking, the issue of transit was resolved in 1972 when both sides agreed on a mutually beneficial arrangement for the use of their waterways, railways and roadways for commerce between two countries and for passage of goods to places in one country through the territory of the other. Inland water transit has been functional, but the rail and road transit is still waiting to be operational.
Bangladesh's initial reluctance to granting India rail and road transit was on the grounds that transit facility once given was difficult to take back and such a facility may encourage terrorism and insurgency.
Other concerns included damage to the roads and bridges in Bangladesh by the increased traffic flow from the Indian side.
The reason for delay was that Bangladesh's infrastructure was not yet prepared to take the load of the increased traffic that will follow with the granting of transit to India. Addressing Bangladesh's concern, India provided a credit line of $1billion to Bangladesh for development of infrastructure projects. But the credit line could not be used to its potential because of the strict conditions India imposed, to the effect that 85 per cent of the raw materials for the road projects has to be procured from India, on the ground that it produces all the materials necessary. Bangladesh has countered by claiming it too has the necessary raw materials. It could earn $44 million per annum for first five years if it grants transit to India. From the sixth year, earnings would be around $500 million, which could rise to $1 billion.  Transit would not only boost connectivity between the two countries, but also offer opportunities for regional connectivity and help Bangladesh develop Chittagong port into a regional hub.
The  Chittagong  port  can  become  a modern  busy  port  like  Singapore  and  China  serving  the  SAARC  countries.  Huge  foreign  investment  may  be attracted by Bangladesh and  finally, a throbbing  service  sector like banks, insurance, hotels, rest houses, petrol pumps etc. may develop around the Transcontinental roads and railways.  There  is  an  estimate  of  direct economic  gain  from  transit  fees.  It ranges from  500  crore  taka  to  4,666 crore taka.  The  mutual  transit will  also give Bangladesh  a  much  shorter  route  to China and an initiative to link Chinese province  of  Yunan with  Seven Sisters of  India,  Myanmar,  Thailand  and Bangladesh. 

Conclusion

India-Bangladesh relations have more than an academic strategic content. In the long run, India’s national interests primarily lie towards and beyond its eastern flanks to South East Asia and the new geographical and strategic construct namely Indo-Pacific Asia. India thus needs to strengthen the various regional groupings in this region like the ASEAN and the BIMSTEC (Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation). Importantly, they should work together to resolve all the issues.