HELSINKI: The port of Helsinki became the busiest passenger harbor in the world in 2017, narrowly surpassing the British port of Dover, Finnish news agency STT reported on Wednesday. In scheduled passenger services last year, 11.8 million people used the port of Helsinki, while in Dover the figure was 11.7 million, said STT. The main reason for the growth of the Helsinki port are the thriving passenger services between Helsinki and Tallinn, the capital of Estonia. Thousands of Estonians commute between the two cities as workers. The two cities are separated by the 80-km-wide Gulf of Finland. Both Finland and Estonia belong to the Schengen area and as such, there are no customs or ID control formalities, albeit passengers must have a passport or EU identity card. Tallinn has shown a similar growth. STT reported that 10.5 million passengers used that port in 2017. In Dover, meanwhile, the number of passenger has been declining for years. Some ten years ago, some 14 million people used Dover annually. There are plans for a tunnel between Helsinki and Tallinn, but they are still at the feasibility study level. Cheaper alcohol in Estonia is a travel incentive for Finns. There is no restriction on the quantity of alcohol imported, but a person needs to carry all the alcohol bought in Estonia to Finland in order to prove that they are not conducting commercial imports.