Singapore was followed by London, Shanghai, Hong Kong and Dubai, according to the ISCD ranking.
The top five rankings were unchanged from the previous year, despite the pandemic-induced drop in global trade and business disruption in 2020, the Baltic Exchange, a global maritime market data provider, said in a statement on July 11.
The ISCD Index, part of the annual Xinhua-Baltic Report, is published by the exchange in collaboration with Chinese state news agency Xinhua.
The index provides an independent ranking of the performance of the world's largest cities that offer port and shipping business services.
Singapore has consistently led the index, thanks to the size of its port, number of internationally focused shipbrokers, financiers, lawyers and insurers based here, and supportive government policies, according to the Xinhua-Baltic Report 2021 released on Sunday.
Baltic Exchange chief executive Mark Jackson said 2021 rankings were made on the back of the global Covid scare and major disruptions to lives and businesses around the world.
'Notwithstanding these challenges, the huge infrastructure of people and equipment that supports the global seaborne movement of billions of tonnes of trade held strong,' he said.
The Baltic Exchange, which is headquartered in London, was acquired by Singapore Exchange in November 2016.
Senior Minister of State for Transport Chee Hong Tat said: 'As the world's busiest container transshipment and bunkering hub, the Port of Singapore has done well to support global seaborne trade during this pandemic.
Maritime and Port Authority (MPA) of Singapore chief executive Quah Ley Hoon said that Singapore's status in the global maritime industry is due to the combined efforts of an ecosystem of many strong partners.
She said the MPA will continue to work closely with its partners, including supporting the industry on its immediate challenges facing seafarers, and its transformation along digitisation, decarbonisation and capability development.
Baltic Exchange Asia head Su Ling Lu noted that Singapore continues to develop its maritime industry with a focus on technological advances in future shipping fuels, innovation safety improvements, nurturing young talent and workforce transformation.
She said Singapore's score of 97.2 was far ahead of the average score of 58.8 points among the 43 ports rated in the index.