Bangladesh and India have begun their first-ever joint census of areas along their border to resolve some territorial anomalies.
Tens of thousands of Bangladeshis live in 51 enclaves in India while India has 100 areas within Bangladesh.
The residents of these enclaves are in effect stateless and lack access to public services.
Both countries are close to a deal to exchange the enclaves as part of long-standing boundary negotiations.
The census will be held over three days. It aims to find out the number of people living in the enclaves, who often have little access to schools, hospitals and other public services.
The enclaves are historical anomalies of the partition of the subcontinent in 1947.
Bangladesh Home Secretary Abdus Sobhan Sikder told the BBC that India and Bangladesh had agreed to exchange the enclaves in 1974, "but it was not implemented".
Now, the two countries are inching towards a deal to exchange these enclaves as part of their efforts to resolve their long-standing boundary issues.
The question is - what will happen to the people?
The two governments say it is up to the residents to decide where they want to live.
The two countries hope to reach some sort of an agreement to exchange these enclaves during Indian Prime Minister Manmohan Singh's visit to Dhaka in September.