The SCO looks after registration work related to foreigners other than Bangladeshi, Pakistani and Nepalese nationals, and performs such functions as extension of residential permit, granting of multi-entry visa, no objection to return to India, visa conversion, granting of restricted and protected area permits, issuance of PIO cards to foreigners of Indian origin and their spouses, issuance of police clearance certificates to Indians who are residents under Kolkata Police jurisdiction, processing of ‘Overseas Citizenship of India’ applications etc.

As the civil authority and Foreigners Regional Registration Officer, Kolkata, the Deputy Commissioner (DC) SCO passes deportation orders for foreigners and liaises with the Foreign Mission, and issues shore passes for marine crew there are international crew signing off and signing on the ship at Kolkata River Port Immigration and issues dock entry permit.

SCO does the work of International Passport enquiry on applications received from Regional Passport Office, Kolkata. The passport enquiries are made in respect of applicants residing within Kolkata Police Jurisdiction.

Immigration forms the vital factor of manifold functions of SCO. DC, SCO is also the Foreigners Regional Registration Officer, Kolkata and he looks after the Immigration matters with incoming and outgoing foreigners as well as its various aspects.